I have seen games made with RPGMaker that have a slower walking animation, are you sure it is not possible?
Also did you say RPGMaker was developed in Windows XP!?
I have never used RPGMaker but let's be honest, the way you talk about it leads me to believe that it's not a good game engine.
It sounds like very stiff. Are you sure it won't hurt the development of your game?
Also if you need help with sound effects, tell me. I usually use copyright-free sounds and distort them in some way for my games. I can also compose some original music for your game! Though I don't have many virtual instruments.