You can use a gameshark to change in game wrestlers moves,however the gameshark can only hold so much memory per single game in use.so mainly I'd just change certain taunts and finishers to replicate that of your desired caw.
Now I'd like to point out that if you really wanted to change a whole bunch of moves of the ingame wrestlers the only way is by using a N64 emulator on a PC and of course the WM2000 rom.
Finnally if you know a little bit about Gamesharks its pretty easy to figure out how to get the code to change moves.
Also, you can make your CAW your tag partner and then just never tag them. Then they'll get pissed and challenge you to a match. Afterwards, they will appear in Road to WrestleMania. Also, you can play through it again after you beat it and the CAW should be there.