Ni no Kuni: Wrath of the White Witch

Hey there, I know there have been some topics on the board with regards to this issue, but there still haven't been any solid/confirmed answers.

Main Question - What is the true statistical difference between the two? (Gold vs Reg)

Also, for those who have the DLC pre-order familiars from the WE - Since you are forced to lvl up your Gold Mite before he caps, how can you get a new Gold Mite (or re-level a gold one) so you can maximize his stats? --> People's solution to this is to just go find a new one later...but what if I wan't to retain the gold version? Is this possible?

(I hope these questions made sense :P)

Cheers!