every cat you can become lovers with that i know of:
cottonwillow:being a male (i think)playing the number game a bunch
dustfeather:being a female just asking him
duskfall:being a female declining to battle train and saying yes to go on the shore
breezesong:being a female and asking
fallenfeather:being a male and clicking them and when they do say yes and repeatly answer yes
nightwhisper:being a male (or female idk) and asking
nightmare:idk what gender tou have to be but accept his offering
cats idk if they exist:
max:waiting until like day 18-19 and then go to where nightwhisper is and then you can ask
(I DONT KNOW ANYMORE CATS)