I advise you to use the Flyer minions that can hit airborne and ground-type enemies, and they can perform effectively when dealing with hordes.
The Summoner’s main Archetype Trait Regrowth, which provides a health regen bonus on top of this build’s life steal is a welcome addition for more survivability in combat. The Minions can contribute to the Mod Power Generation when they hit enemies and also take enemy aggro, giving you a little bit of breathing room when dealing with hordes. The goal of this build is to charge the Nightfall’s Mod Power as quickly as possible and activate the Dreadwalker Mod. The Summoner will be slotted as the second Archetype for this setup.