Oh wow, we have the exact same family combination!!
Raise your bonding to 100% if you can, then keep trying the dating show with your Mametchi until you get offered a Chantotchi. However you can only try three times a day so if you don't get shown a Chantotchi, either you have to set the time a minute before midnight then wait a minute, or a minute before the family wakes up and wait a minute to be able to use the dating channel again- I'm not sure.
If you have any friends with a Mametchi or a Furawatchi on a v5 I suggest you send some of your characters over to them so they can get some special families as well. If you have a friend with a Mametchi, send your Chantotchi and if you have a friend with a Furawatchi, send your Sukatchi.