Adding more commands to battle menu?

I don;t know if there is a way to do this but it is annoying how one character's slot if replaced can screw up the game from progressing, thus I'd like to know if there is a way to add more commands without taking any away. I only see 4 slots, but with the advances made in hacking so far i doubt this is impossible.

Also if there is a way to equip/dequip commands sort of like ff7 I'd like that too

As far as I know that would be impossible, as for your other question I am unsure whether you can do that or not.

The biggest issue with expanding the command window -- actually expanding the window itself aside -- is SRAM space. Each character's battle commands are stored in their SRAM block alongside their stats, equipment, etc. As it stands, there's only enough space for four commands. Now, theoretically, you could a) move commands to a different, larger part of SRAM (problematic in that I don't think there's enough free SRAM left, much less in a single block, to store five commands per character); b) store a fifth per character (and potentially a sixth) in one of the free SRAM blocks (theoretically possible but would require some pretty extensive ASM hacking to code the exceptions); c) store all of the battle commands elsewhere, but compress the character info blocks to free up the space that would otherwise have been used within the character blocks to store battle commands (requires LOTS of moving data around, some small adjustments everywhere a character block is referenced, etc. etc., but may actually theoretically be the 'easiest' solution -- assuming you can expand the command window).

As for equipping/dequipping commands, the code already exists in the game for that -- it's used in Gogo's status menu. However, if you want to have some way for characters to 'learn' commands individually, you'd have to code that from scratch and set aside a byte of SRAM per character. As it stands right now, commands become available to Gogo as soon as a character is recruited, IIRC.