A few of us have been working hard to figure out bits of the code to make the game more... eccentric and elaborate. So you're welcome to join us if you like.
I'm not a 100% sure what you're actually asking with your question? Yes you can replace models, but its actually pretty difficult to do because you have to change files that arent meant be edited using text editor. Essentially you just change the reference of a file to another place (that has the pre-mission models), but I'm not sure why you would do this? Is that what you mean?
Well... should be easy enough to do, but I'm 100% sure of what model references you will need to change. A litte trial and error might do the trick, so If you try it out, let the rest of us know how you go.
I would really like to get my "hands" om the information that you are writing about:
"So roughly what I know:
can edit all bug types and stats (know what each line relates to)
Can edit some bug holes (so you can change experience you get and health of the bug hole).
can edit all troops you begin with and all you meet in the future (all stats, including giving them armor)
can edit all weapons available in the game (like ammo, when they become available, damage, range, etc)"
I cant find this info google...
Would you be so kind to share what you have learned on this forum?