You will want to keep your Jirobo up to date, he is great at 9 tails even if you stop using him in your normal team, until you get Yamato at level 70+.

As for summons, the most used one is definitely Bull, and in general summons that chase Knockdown (White Snake and Katsuyu) and Low Float (Ninja Dog, Shark, Deer) give you most build options, since they combo of your mystery.