Board Thread:Questions and Answers/@comment-28053036-20150312032458/@comment-26044227-20150312051321

Ah, they'll choose it regardless of what is shown as advantageous or disadvantageous (unless the one they pick is disadvantageous, in which case they'll pick the other related formation with a similar change in stats).

I'm not sure about the second question...? If you've played Kancolle before, Touken Ranbu sortie maps have no requirements on sword types needed to clear maps. I believe there are only one or two maps total that have branching rules that will draw upon your team's composition (but they are never essential to reach boss nodes).