Help with bad IV W!Chrom & W!Robin

I finally pulled some Christmas units and got a -Atk/+Res Chrom, and
-Def/+Res Robin. I thankfully have Black Knight and Arden while they were here. I'm trying to have a stable Armor Emblem team, mostly for story mode/events/non-pvp, but don't know how I would build these guys. I'm okay with having W!Robin, W!Chrom, BK, and my P!Inigo until I can get another decent member.

I'm a f2p player but I'll try to keep pulling on this banner before it's gone I'd like to invest in these as they are for now.

Any idea's would be be greatly appreciated guys/gals! :)