The way I see it you are making a separate mod. If you publish it here then people will discuss it here, which hasn't really much to do with the mod that the thread is about.
Yes I can agree with you regarding where it's heading now.
Then again I somewhat misread your post as being an actual mod launch, instead of the enquiry that it was. Sorry, my bad.

But overall you might still get more feedback from other if you post your files in the mod development section.
Yeah I wasn't launching anything here - apology accepted.

I'm just confused and basing myself on the resources that are present - the Flagship Randomizer stuff is intricately linked, and I don't claim to understand it all.
That particular scenario should be fine. If loading a thing causes crashes than that might be connected to the game not being able to find ids referenced in the asset. Like if the boss calls a weapon ID that doesn't exist. Maybe double check if all ids are spelled right. The crash behaviour extends to child objects, so if a weapon the boss uses references a wrong animation or projectile id that might also cause crashes.
Will double-check, but I'm fairly sure this is all OK.
If you can't locate the problem you could also try rebuilding the mod piece by piece, adding elements one at a time to see whether they function. Maybe start by just changing the boss weapons to verify that those work, then add in the room layout. Also remember that you can edit ship blueprints outside of superluminal, that's often fast to correct small stuff or make minor changes. If you absolutely want to make sure the mod works you could start by making minor changes to the vanilla boss blueprints, without using superluminal.
I did make some changes outside Superluminal, although it doesn't have the visuality of Superluminal (you can only do so much when you can't see what room it is you're really editing). However, fair point on one step at a time and starting with modding the weapons only from the start. I can work with that.
As for the rest - yes I noticed the data folder thing, and I'm not planning to change the overall size of the boss (only planning to change where rooms are) as that sounds really superfluous to me, anyways - I just want to offer variations on Bosses to provide a variety of different challenges. So I don't think that should be a problem.
Mind you - how the Flagship is named to be recognized at all is rather confusing to me. Does it need to have nine iterations to work (EASY, NORMAL, HARD, plus all the DLC..., and 1, 2, 3), or does it load like other normal ships...? I guess I'll find out slowly...
And finally...
I'm sorry if this came across as rude.
Sorry if I was, too.