Shale: You've got Lilina, right? Go in with her and Minerva. From the starting |- formation, make sure Lilina is in position on the eastmost spot, and have Minerva go from the southernmost point 2 tiles east to bait out Ursula once she is. She won't get doubled, and should easily survive a hit. That'll bait the axe knight out, which Lilina then blows up. The northern ninja (with Escape Route) will come into position to get attacked by Minerva, fairly safe from retribution (Camilla is actually better here, because she outright OHKOs with a Brave Axe, but Minerva should be able to weather the hits.)
The ninja has 39 speed and your Minerva has 41 even, so if you have anyone with Hone Speed or Rally Speed you might want to bring them along and have them buff Minerva beforehand so she can go for the OHKO on the ninja. They can be safely positioned for this in the center of the |- formation.
I had Camilla for this strategy, and she OHKOed Ursula after hitting the ninja. Minerva should be able to pull that off as well. The problem there is that you expose yourself to the red cavalier, so you'll have to devise a way to either get your unit out of the way (Dance, Draw Back) or wall them off with a blue, preferably a non-infantry one. I brought Olivia/Catria as my other two picks, and after Ursula died, danced Catria into position to block off Camilla (or your Minerva, in this situation) from being hit by the cavalier. At this point he should suicide into your blue, and you've just got to pick off the remaining ninja (or ninjas, if you couldn't OHKO the other one). Not exactly easy, but still doable. 4* is a nice upgrade if you plan to use Ursula at all, so it's worth trying.
