Well as clear allies:
Dragon(Revos) - Kuzan - Koby (SWORD) - Strawhats
RHP - SHP
Imu-Akainu (and his marine faction)- Godknights (Garling and the evil Shanks :D)
clear Match-ups based on placing
Akainu - Sabo
Dragon - Evil Shanks
Kuzan - Garling he obviously likes to be absued or abuse the elderies lol first Garp (to maintain the cover up) and later Garling to officially announce his real position
Good Koby - Evil Imo
Luffy - BB
not so clear but possible :D
Shanks - Buggy(well maybe Mihawk as rival and Buggy for comic relief)
one thing but is confirmed The marines will split and part will join the revos and Dragon and that is Sword and Kuzan (i think he is trible agent, BB-pirate Revo and Sword right now but he is just undercover in the BB and officilly a memeber of the revos and sword)
but why the hell Koby vs Imu maybe just indicating good and Evil or Imu was really young when he got the imortality and somewhat distant related to Koby
to be honest i assume Koby is a D and Imu as well (just a traitor) and Koby will be the desedant that will correct the wrong that Imu did
well i think like Orochi and Tama being the of the same family
I think that apply as well for Shanks as a good figarland descandant in a family of D. traitors
Marshal D. Teach is the D. traitor in the new era and might ally himself with Imu maybe for selfish reason as an opportunist