Are Mon Mothma and RFs good enough to have in your top 80?

Depends on what gear level breaks your top 80.

Mothma is easier to counter with Jawas than Geos are, given the team's low damage output. As a rule of thumb, (RF gear level)-2 is enough for jawas to reliably work. So if you plan on keeping a multiple zeta RF team at g8-10, it's probably not worth the investment.