I have a few matoran ideas
Stormer: a retired Ihuan soldier who is now in charge of training new cadets (Including Toudo and Izotor)
Bulk: Stormer's friend and former teammate who keeps fighting regardless of his age.
Stringer: Island-famous musician from tiro.
Furno: One of Jaller's finest soldiers.
Breez: Kanaean chief rahi tamer and an adventurer. (This just might be my favorite g3 matoran design to date)
Rocka: A vigelante who protects those who are being hunted by Dekar and his inquisitors. Friend of Dune, Pekka and Kodan.
Nex: Young motari engineer who secretly helps Rocka.
Evo: Nahoan chief helmsman, usually steers the main arbiter ship.
Surge: Ship maintenance worker.
I hope that you like them and that you don't have too big of a problem with having them in g3.
Working on it.