Does completion of the RYA Competent Crew Course set the standard of a competent but not expert crew?
No, this is an individual qualification which means that a person can be a useful member of a boat crew, not the person in charge. It is not a racing qualification

Is making a sternboard to get out of irons 'competent' or 'expert'?

Competent, as it is an essentila skill

3.  Is 'pulling the trigger' in a Laser 'competent' or 'expert'?
Competent and a possible infringement of RRS 42, Propulsion

Does anyone have any other ideas about indicators one way or the other?

Anyone disagree that the standard might drift a bit between a club race and a national championship race?
Case 103 states that the experience of a particular boat's crew is not relevant in determining 'room'.
However the Call Books (MR, TR and RS) all point out that in these exceptional forms of racing actions that in fleet racing are abnormal and therefore unseamanlike will be considered normal in these. However, any manoeuvre that puts a boat or crew at risk of damage is unseamanlike.

I cannot resist sharing one  jocularcomment - the concept of room, and therefore mark-room does not apply to some skiff classes: on the grounds that room is the space needed while manoeuvring promptly in a seamanlike way. As it is not seamanlike to put to sea in a skiff all manoueuvres are unseamanlike!
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I think this is a nice topic for open discussion.  The rules rely a lot on the criteria and judgement of sailors and the member of the RC and PC. 

I can very easily think about a new group of people, all new to racing sailboats and even to sail sailboats, that decide to organize their first competitive event using the RRS.... thye all read the rules... cases... recommendations.... and set out to race...    Let's assume they run a perfect event and all know the rules and how to apply them, When assesing if someone acted "seamanlike", or what a "seamanlike action" should have been, it is clear to me that the criteria and judgement applied within this group will be much different that a group os expert sailors at, let's say, an olympic event.

My point is that for example what a novice group think "enough room" is, is different to what it is for an expert group of sailors.  This would be no problem if these sail separately, but when sailing together opinions will be strongly different!  

I would like to see a more objective way of applying rules.... one that does not rely on criteria and judgement.  

Am I asking for too  much?

RE: Q5...
I strongly AGREE that "the standard might drift a bit between a club race and a national championship race."

Even though competent doesn't mean "average" (and average could be defined as mode, mean or median), we might consider that as the average sailor in a group improves, the level perceived by that group of a competent sailor might also increase. This is perhaps more clearly visible across eras or between types of boats, but can easily be applied to different groups of sailors as well.

So Nicholas, at the lower club level, what about questions 1, 2, and 3?

Suppose it is agreed that the standard shifts depending on the person or the circumstances, then a "reasonable person" test could apply. I.e., evaluate the situation and the experience and qualifications of the crew member and compare this with an expected typical expectation. This will allow for a crew member to be an "expert" in a club race but only "competent" in a national championship. However, this is subjective and only useful retrospectively.

Reading this thread I had the thought that one challenge for judges might be not to unconsciously put a higher standard on a known expert crew … just as it is to expect too little of a known novice crew in a mixed fleet of experience. 

Fighting our tendency to think “Joe should have known better” or “Beth should have been able to execute that in her sleep” when the sailor(s) in question are well-known accomplished sailors might be a mental trap we can fall into without realizing it. 

Judging, umpiring or refereeing is always based to a great extent on the judgement of the official.
Umpires and referees rely on pattern recognition, they recognise a scenario and apply the rules based on the established pattern of response. In this way they can give a rapid response, usually within seconds.
Judges establish facts based on the evidence given, together with their experience as sailors and judges. They then apply the rules as written,and as interpreted by cases. Some cases are authoritative, others (RYA USA, Canada, for instance) are illustrative and persuasive. 

Consistency is achieved by a long training process, in which the transmission of values, agreed  conventions etc are passed on by the more experienced officials

Case 103 states neither the experience of crew, nor their number is relevant in determining room. A dictionary definition of competent is:
1. having sufficient skill, knowledge, etc; capable
2.  suitable or sufficient for the purpose 
I would argue that most crews in racing have sufficient skill. They are the crews that do not stand out on the race course - neither for the rapidity and quality of their manouevres, or by their incapacity to manouevre safely and efficiently. There will be fleets in which all crews are competent, there are others in which many crews are beginners. This should not influence our interpretation of 'room'.
Expert sailors will sometimes argue that they can get closer, that there was no risk of collision because they had the skill to keep clear at the last moment. 
The counter argument to this is set out in Case 50. A boat is not keeping clear if the other boat has a genuine and reasonable apprehension of a collision. It is the RoW boat's call as to whether she has need to take avoiding action.
In making this decision, I would accept that the RoW's evaluation of the keep clear boat's crew is relevant.

Another instance: when a boat on port tack hails 'Starboard' then it is unlikely that the PC will accept that an acknowledged expert crew made this hail in error, whereas they might accpet that a novice crew did make a mistake (see Case 47)

I've been racing 30 years in the US, but am unfamiliar with RYA courses, as well as with the terms "sternboard" and "pulling the trigger".

* we they (clarified since I've been working elsewhere for a while and don't volunteer teach this class) teach getting out of irons to people who have been on the water once, and expect them to demonstrate it before using a jib.

Nick, thanks for sharing your "irons" presentation .. nicely done. - Ang

Thank you sir! Iirc, some teenage students did this. Not sure why they weren't credited, so this one might have been staff.

In spring 2020, I worked at CBI and led digitization of our learrn to sail classes; then these "step 2" excerpts over the summer, largely by volunteers including MIT's sailing team. These are able to be self-taught versions of the live, in-person classes offered.

Volunteers also teach a Learn-to-race class developed by a brilliant teacher (and sailor) who is now Courageous Sailing's education director. We digitized those presentations, but it is still a self-taught class. Pretty proud of the work we did that year; sorry for the shameless plug. It's a lot of fun, and we are one of the few racing groups that seems to be growing and have plenty of crew available.

Nick, Might want to suggest to them to add pushing the main forward to one side of the boat to instigate the turn and accelerate the movement while turning the rudder in a complimenting way in their next edition. 

Ang, it's possible you're overestimating the level of skill and athleticism at play here. It is critical at a place like CBI that we teach methods which can be done by anyone who can safely climb onto a centerboard Mercury ranging from ages 10 to at least 85. And also, this is sailing day ~3 on a shifty and gusty Charles River, filled* with other sailors who might be on the water for their first day, or winning a college national championship at MIT -- we don't want them executing any faster at that level.

For sure, we expect racers to have a level of competence with this maneuver that may well include backing a sail, and of course, to understand that while they're going backwards, they have no rights. However for this beginner lesson, less is more. You wouldn't believe the discussions between education PHD's, world-class sailors, member committees, feedback from instructors and students that have gone into the multi-page teaching rubrics for these classes. They teach thousands to sail every year and for the most part, I think they have it dialed in pretty well for the level.

Having written that, I'd like to amend my answer to OP Q2: it is the level of execution in getting out of irons that divides beginner, competent, and expert. Watch even an intermediate racer choose when to change from leeward helm to windward, based on when their boat goes from backing, to stopped to forward, and you'll see that only pretty good racers get the timing right.

*easily 300 watercraft in a square mile on a busy day, ranging from kayaks to Sonars to Duck boats and other powered launches. It's a pretty wild place.