Yes.

As long as you have one summon on one selective slot, equip that for ranked.
And make sure to have that slot the same summon for each Set, that way it'll always be functioning for ranked.

Now if you're asking which Summon select in ranked affects your PVP team outside of it? It won't.
Hopefully that helps!

whatever summon u have equipped outside of ranked battle is the summon ur using for ranked battle. besides arena gets its own summon. other than that wich ever summon is equipped to ur main is the same as ranked battle