I'm not sure if the Mame family even exists on v5.5. It might not. You see, on the v5, to get a Mametchi you need to have 80% bonding or higher and on the v5.5, if I remember correctly, you need 30% bonding or lower. I don't think Bandai would let you have a better family for less effort.
Since you've got a v5.5, try aiming for the Royal Family. Sorry, I don't know any tips to help you get one since I don't remember any of the combinations.