The Larxene battle always reminds of how beautiful the animations are. The developers were able to create something really marvelous. How Larxene moves, how she clones herself, how the electricity sounds and moves, how her coat motions when she dodges and etc... glorious. Just thinking about how all the clothes and enemy attacks will look like in KHIII makes me really excited!
What do you recommend for Laxeus and Vixen? Just playing these guys on critical mode reminds me of the Data Battles. And those I'd imagine are WORSE!
For Vexen, go into either Wisdom Form or Final Form, and spam the heck out of Firaga. Equip the Bond of Flames Keyblade to increase Fire spells damage 20%.
For Leaxeus, there is one move he does in the beginning of the fight which you can block. The move will always look the same, but will get more dangerous as the raises his power level. More rock are going to come from the ground. . Just try to learn his moves, the ones you can block, and the ones you can`t. You can use either Reflect or normal block. Try to learn recognize the move which he does in the beginning, because if you block it, you will get a reaction command. The attack looks like ripping motion across the floor.
Your level is good enough
When he does the move where he bounds the ground and rocks rise from it, by looking Leaxeus hands you will be able to learn to time your dodges, so you won`t take damage. It might look difficult at first, but once you learn it, it`s easy.
For Leaxeus desperation move, he goes to the air, and crashes down. Run to the center of the arena, and just when he crashes to you, use block. Quickly after that, use reflect to block the boulders that come from the ground, as he pulls his weapon out from the floor. You can try to use reflect to block his whole DM, but I am not sure if you have enough combo plus abilities. Leaxeus is a really fun boss.