They also have the best chapter possible for EXP. 4-5 has tons of Feral Ones, and they're not so bad to deal with either. You can use this to help others catch up.
Especilly if that group has the beastfoe skill. Though to be honest at that stage of the game I was fed up and just wanted to beat the danmed thing (most of my final map team wasn't in that group anyway). I stuck to the defeault teams pretty much but made a few personal tweeks to them.
Haar and Zihark went with Miciah. Harr because I needed a good flying unit in that team (the Falcoknights were pretty horrible

) and Zihark because of A support with Nolan.
If you get really stumped you should be able to pull through with the forced units (every group gets one Laguz Royal who are fairly capable or nearly soloing the map...)