Restarting mission 13 will reset your elites to the ones you use in multiplayer. If you don't have Ronahn equipped you can't finish the mission . . . major downer for me :-(
ugh, hate this mission . . .
Atleast you made it that far. The continue button is still greyed out for me after completing mission 4 three times now, even restarting doesnt help.
Wow, played it five times and received 0 elite XP for all elites when I finally beat it . . .