Finna, Hodir and especially Hymdall seem like exceedingly poor choices as their abilities have a static value, even prior to 7.2 the other followers had the capability to solo 200% missions with two troops, something that's really only increased now that they have access to a third equipment slot.
For example, there's basically no situation in which Hymdall outperforms Crowley unless your troops are being rotated through poorly, since at worst, you send a fresh Valkyr on the mission and Crowley receives the same 15% bonus, on every mission instead of just long ones, or you send a Valkyr and a Valajar and he receives 25%(!) instead, with exactly the same counters.