So far my strongest units are:
5 star Takumi
5 star Tiki
5 star Chrom
4 star MCorrin
I'm tempted to roll and get some more blue and green units, but I think it might be better to wait until top tier blue and green units are featured in the banner. I gave up accounts with Lyn and Roy because I really wanted Takumi, so I chased Lyn on this account a bit and was unsuccessful.
Very solid setup - waiting sounds about right, since you will likely have to spend a bunch of orbs until you get a unit that is good enough to replace one in your team.
Do you have a healer ?I have 5* Sakura...but she is kinda lackluster lol.