So the main question I have is:
What are you looking for? Titans? Defence? Raids? Bosses?
Titans:
I vote for Inari. Her tile damage is the highest of any of the yellows in game (just avoid firing her special so you don’t accidentally make any minions)
Next would be Poseidon. Vivica is too slow & you don’t have her costume. Onatel is OK but just not a massive attack stat.
Defence:
None of them really replace Guin. Soo… probably not a factor here 
Raids:
In terms of which will best fit into a riading team, I would say that Delilah will probably give you the most versaitily in offence. She’s an Average Speed healer (so better than Vivica) & the minions make great meat shields.
Next up would probably be Poseidon to give you a second sniper to pair nicely with Joon & Drake.
Bosses:
Onatel. Her ability to control mana is BEAST, esepcially if paired with Proteus.
Fire Proteus & Onatel at the same time & the enemy gain no mana for 4 turns. Then just wrinse & repeat until the bosses are dead… Using this, I’ve never had any issues with any of the class quests which use Wizards.
In terms of a comparison of the 5, heres a quick snapshot of their stats at maxed:
Expand below for more ordering of the heroes:
In terms of emblems I don’t know your full roster but:
- Poseidon & Delilah will fight with Kingston for emblems
- Onatel will never get emblems from Guin
- Vivica there are heaps of other clerics around so its a well contested field
- Inari doesn’t usually have a huge amount of competition for the rogue emblems HOWEVER I personally wouldn’t be giving her any (in fact I haven’t given my maxed one any)
Link to sheet used for snapshot: