I found that possibly the Extreme Battle enemies are in the remaining RDTs A000 there after.

Is it true?

Yeah, the A***-F***.RTD files are covering the EXBM rooms and therefore contain info on the enemies as well. It's funny to work with these files since they are sort of "cleaned up", because there's no need for puzzles, scripts, cutscenes and whatever. ;) It's either A-F meaning 1-6 comparing these items to the "original" RDTs or vice versa (A-F means 6-1), for example a F150 actually contains the 1150 or 6150 room, it's easy to find it out for example by looking at the textures that are found inside these A-F***.RDT. That's the reason why I asked if there's any sense in covering these rooms as well in my SHM2-pictured list.