Well... See this is a huge discussion that we should probably take into pms if you care enough but I'm pro alignment. Mostly because I don't think it limits a character at all. It's a way to allow certain super natural abilities to exist and it gives a vague idea of your character's nature. If your character sticks out for themselves, they are neutral. If your character is selfless and cares more about others they are good. If your character is selfish and would throw others into the tracks to save itself, it is evil. Simple as that. The reason why real life humans are hard to define with the alignment system is because we are almost all neutral. All of us act differently depending on the situation, most of us aren't willing to sacrifice and most of us aren't willing to sacrifice others. But anywho, that's irrelevant. Let the player decide and no alignment system probably for the best!
Just make sure to make a shit ton of these! Maybe take the DND list? The 5e list is:
Abberation, Beast, Celestial, Construct, Dragon, Elemental, Fiend, Giant, Humanoid (with a sub template for goblonoids to include bugbears, goblins, hobgoblins etc), Monstrosities, Oozes, Plants and Undead!
Do indeed split them up. But make sure to make the powers not too specific. A vampire is different from a zombie but they would both be "flesh undead"