i've had kuribotchi lots. apparently he won't come in the first gen so if you are in first gen you might be out of luck for him this time. the way i got kuribotchi was to keep it's hearts at 2 full all the time. both hunger and happy. i've also gotten him by keeping the hearts at 3 full. but you have to be consistent. don't let them drop lower than 1, or 2 if you're keeping them at 3! also i kept my tama at ideal weight, that is i played with it till it shook it's head at me. always cleaned the poop, it never went to bed with poop by it. btw if it does go to sleep with poop by it just set the clock back and clean up then you can put it back to bed. hope this helps, but if you still have trouble feel free to pm me and i might be able to give you more specific details. i do think this will work for you though. i've never gotten kinakomotchi, but i would try keeping it's hearts at just 1 and see if that doesn't get him. i'll be trying that on my next gen i think. good luck!
yummyhunny