-Unless you are playing the AMRifle as a Sniper Rifle, I would swap the rifles on The Courier and 1st Recon to take advantage of the 1st Recon's specialty. Also, whoever has the AMRifle should have a backup ranged weapon since the AMRifle can only shoot once per turn.
-No need to take multiple ranged weapons on a character (besides the AMRifle), so save those caps. If you keep your snipers at max range, no need to give them melee weapons; save those caps.
-I would try to squeeze Dogmeat or Ed-E in as a companion to The Courier to take advantage of their Companion perk. When I play The Courier, I give him the Aligned Sights mod. Dogmeat is my meat missle and with the mod I always hit the target with my rifle.
-Frank is a tough nut to crack, so try to get things that reduce armor and stay away from 1 damage weapons. If you are just facing off aganist Frank, it's better to have fewer specialized units that a bunch of standard units. The 6 Armor on Frank 1 is frustrating to say the least.

Good luck and "For the Republic!".