Some Absolute testing. EunhwaTU right now is bugged, for whatever reason after her burst shot she does not fully reload her ammo and in my case only goes to 8 ammo despite me having 17 total. I've checked other units with weapon changes and all reload to max ammo after their weapon changes back except for MW who also drops some ammo. But after checking past videos of MW being used she was fully reloading back then so this bug is newly introduced with this patch most likely and so far at least EunhwaTU and MW are affected.
Other than that I think the team has some potential, I think at equal investment and OL lines EunhwaTU will do more dmg than Grave unless there's something for Grave to pierce. EmmaTU + EunhwaTU have better buffs than DWife + Grave, but since you have to drop the 3rd B3 to make up for the missing CDR the overall dmg is still lower. And Liter + Grave are just better period.
They gotta fix the bug and VestiTU will have to make up the dmg lost for dropping the 3rd B3 somehow in order for this to become the strongest fire comp, which would basically mean she needs to do as much as RRH does which seems unlikely, but even if it won't be the strongest it'll still be a good second fire team.