Yes, that map can be annoying, but what you have to do is split their units up. I take two of mine up top and move two to the bottom. If you go in the middle, you are going to lose a unit.
Yeah, that's how I handled that one. Sent a fortified Rein up top with Xander to pull the other Rein over. Sent Camus and Olivia low to pull Azura down. After killing Rein I threw Camus back into the middle to deal with Ryoma and Takumi...WoM3 Azura then warps in and takes some pot shots as well, whoops. He survived with 1 HP after Fury haha.