My current 5*'s are
Camilla
Tiki (young)
Seliph
Julia
I'm looking at running Seliph/Julia/Tiki/Blue right now.
I obviously need a blue and I have a few decent 4* choices:
Effie (+Atk -HP)
Robin (+Spd -Res)
Cordelia (+Def - Spd)
Nowi (+Def -Res but not sure)
Corrin (+Def -Spd)
I think the 2 biggest common threats to my team would be Takumi and Lucina. Effie helps deal with them and a lot of other units. Cordelia should be able to 1 round most falchion users but isn't the best Takumi counter; also has bad boon/bane. Robin counters Takumi but probably won't be one rounding any falchion users.
I'm thinking Effie is probably the overall best choice but I dunno.
You should probably go with Effie for the reasons you stated.
But if you don't like her one movement, robin male isn't that bad. Like you said, he takes on Takumi very well and can help with falchion users. If you have robin hit them once for good damage your other members can finish them off.
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