There are several ways to go. I had Hydro, Huntsman and Necro on Lohse (my summoner), for ranged support and bone widow (I play pure physical damage) but changed it to Summon/Hydro/Scoundrel, because I never used the bone widow and she is too squishy for me without a shield. So she can support with Hydro skills and deal the one or other damage with her tiny one-hand dagger.
Important for me are points in Hydro, or Geo on my main, for better armor renewal. It helped me win some fights without casualties. Resurrection scrolls are expensive.
