My team when it comes to merge isn't that impressive. I average 692-694. Highest possible I saw was 702 and lowest was 690, but I didn't take that on because it had a Xander lead which led me to suspect there's a Reinhardt waiting to screw over my 5 win streak. 700 is also somewhat rare. I've got that high thanks to a stockpile of crests and cherry picking - My goal is it to just stay at 18-19. At least I won't even have to try next tier there's no way I'm staying in Tier 19.
Anyways to answer your question Ryoma+3, Azura+1, Anna and Roy+2 is what got me that score. So this is probably the only situation that allowed this to happen as I like Roy a lot and got a lot of investment into him. Rest was just having a stockpile for the Hero Fest and getting lucky. Anna... Is my best Green. At least she counters the +7 Reinhardt I encountered, but it's not like she's going to give a much higher score any time soon if at all.
I don't have many green units and only a few good ones the next best one would be Camilla and after that a decent Fae. If push comes to shove I might invest in Fae, since I liked her in Binding Blade although I'm put off that she says "rawr" and stuff here. Also not a fan of Zephiel seeming way more unstable than he was in the translation of Binding Blade that I played so he's also a unit that I was looking forward to that I came to dislike in Heroes. His voice acting is pretty nice, but some of the lines are just weird to me. I know this is the guy that snapped and wants dragons to rule, but aside from that he seemed more stable than this.