Ahem. The ghost character can be gotten a similar way to Kuchipatchi, except the ghost character can be gotten on even generations. Kuchipatchi's method is below if you do not understand.
How to get Kuchipatchi (I have him now): Take really average care of him, but discipline him every time he needs it or he might become a Tarakotchi. Let him go to sleep with a poop next to him twice and do not let his hearts drop below 2 or 3 full/empty (depends on how you look at it). There are a few exceptions, like the Megatchi who needs similar care to get, but this should hopefully get you Kuchipatchi. you can get Kuchipatchi from a Babytchi --> any of the child characters --> Young Mimitchi, Obotchi, or Patapatchi (be careful, Tarakotchi can be gotten by those characters too) --> then you will hopefully get to KUCHIPATCHI!
How to get Mametchi/Mimitchi; These two characters need the same care, except Mametchi you can only get on odd generations and Mimitchi on even. Do not let any his hearts drop below 3 or you could end up with a different chararcter. Do not get him sick, toothache or sleep with his poop next to the bed. Discipline him every time he needs it, that includes when the attention icon lights up with out a good reason and 'Time out' him. Fill his heart up straight after doing that. YoU hAvE tO tAkE aBsOlUtE pErFeCt CaRe To GeT MaMeTcHi Or MiMiTcHi!
Any characters except Young Mimitchi, hinotamatchi, Hashitamatchi, Hinatchi,and hikotchi can be used to get Mametchi. Young Mimitchi, hinotamatchi, Hashitamatchi, hanatchi and Hikotchi are the main characters to get Mimitchi from.
How to get Tarakotchi: Let your tama be sick as often as you can without killing it. Be the worst owner that you can be. Tarakotchi will be guarenteed your tama if you never discipline it, time it out for no reason, not praise it at all, but don't kill your tamagotchi. Tarakotchi may be gotten most by Nikatchi and Piroiroritchi, but you can still get it from any character on the odd generation. WARNING! IF YOU ARE NOT AN EXPERIENCED OWNER OR YOU DO NOT UNDERSTAND THESE INSRUCTIONS, DO NOT ATTEMPT TO GET A TARAKOTCHI. YOU MAY KILL YOUR BELOVED TAMAGOTCHI AND LOSE EVERYTHING! EVERYTHING I TELL YA!
These methods might not work, but it was how I have got my tamas. Don't say I didn't warn you!