What I've been doing for my 4th race is a bit hack-ish, but it worked great so far and hasn't cause a crash.
For your player.entity, duplicate one of the existing ones instead of starting fresh. This will give you a great framework to start creating from, as you can just replace references as you go along. I created my 4th race using PHASE as a template, and have since created new frigates and battleships. All I had to do was update the entity and it now refers to the new .entity files for the ships.
This way, you are guaranteed not to miss anything. The race will be identical to PHASE for a while, but I will chip away at it and create new content as I find the time. Think of it as doing a total conversion mod on an existing race. 