They spawn in almost every single biome except ocean biomes,End biomes and nether biomes. You can find them in either clowders of 5 or just one lioncat. like wolves, there's a 10% chance to find a baby variant. their mane colour changes according to the biome they're in. (eg: if they're in a cold biome it will be a dark cyan and if in a biome like a desert the mane will be yellow with pale yellow fur) They won't attack you, if you don't attack them of course, Then all nearby LionCats will attack you and they're really fast so running away won't help. You can tame them using raw fish like cats! Or if you're a monster...

They drop an item called the LionCat's heart which can be brewed to make potions of Healing (or strength or speed,i haven't decided yet)

if you tame one it will do what pets do roam around,commanded to sit,or follow you. The special thing is that it will attack any mob that attacks you! and can chase away creepers like cats! they can be healed using cooked meat or fish

but does that mean you should replace them? no..

unlike cats, they can't give gifts when you're asleep,nor can they scare phantoms. and they're a bit harder to tame than wolves and will get food poisoning if you feed them chocolate cookies, raw meat or fish (only applies to tamed LionCats),and normal in game poisonous foods

they won't change mane colour according to the season (if you bring a desert LionCat to a Tundra it will still remain in desert colours)

Yes, They're breedable and are not affected by Fall Damage

Untamed LionCats have 7 hearts and Tamed ones have 10 hearts