Harby needs protection -Shield Guards, Hierophant for healing, defensive warjacks (Vigilant, Devout). Warders are excellent solos by themselves and golden with Harby (as they also help her survive melee assassination). Without any of those, she's just asking for an easy assassination when low on health.
We have quite a few universal warcasters. Faithful Masses can be nice and shooty with Reznik2 or Sevvy1. Guardians need a caster who improves their damage output and are good to go as well (maybe adding an anti-ARM merc option). Judicator with Amon in Creator's Might is really fun. Thyra in Exemplars is fun too - incredible speed on those supposedly slow Exemplars.
Menoth? Haven't heard of such a faction. For sure there's the Protectorate.