Hello! I'll answer your questions in order, and sorry for the delay!
1. Yes, speeds are normalized, no more walking faster diagonally, than you would walk in a straight direction. This is resolved by the Collision Altering Plugin, not character motions though.
2. That is correct, you need both plugins in order to get both the pixel movement, AND custom animations.
3. Technically this can be done via eventing I believe yes, if you set a parallel event that is constantly running, you could check the players current motion, is idle,( $gamePlayer._motion == 'idle' ), and increase a variable when this condition is met, when the variable reaches 60, you could play a new animation! :)
I hope these plugins will find use in your project!
Thanks for your inquiry! :D I hope my resonses were helpful