Random characters

[shin hanazumi]

Pretty sure only id: 52 of 50-59 is armored.

oh, i forgot about that. I was search for armored ids once. Long time didn't touch LF2 stuffs.. (it almost three years lol). So, yes, just like bashscrazy said, 50-59 are cheat unlockables too.
About the three same ids, i think you shouldn't use existing id, it'll confuse the engine probably. You can try using Davis's id for Woody so you have two id 12s (12? I forget about it too ), then record your fight with both of them in any mode. Look at the playback and voila! It's two Woodys.
I'm sorry to not answer your main question, i didn't really get it. Anyone maybe? I'm just trying to help.
Edit: err.. You mean you use double ids again [the id 5]? I think it's same case with my recording example. The engine only read the first id [id 5 in this case] owner who "own" that id. So, just like the davis-id-numbered Woody, Davis wont be one of the random chars (it's my opinion, correct me if i'm wrong) because the engine read the id 12's owner is Woody (his line is called and read first in the data txt by the engine than Davis's)

[Mkbewe]

Let me give an example. You have 11 different characters (10 standard + 1 f.e. Maverick). If you give dor Maverick id: 5 and if you write the line of him upper than Rudolf's id in data.txt, LF2 program will choose ONLY Maverick in Stages. But if you will play in versus mode with random enemies. LF2 program will choose both of them, because they have id between 0-24.
And i don't understand why is LF2 choosing only first characters in stages...

[A-Man]

Because this is how it works. Characters noted first in a data.txt would be the ones opointed or brought into a stage (IDs should be unique after all). The character selection screen, however, simply goes over all what is loaded and lists them for you.