I’ve been running a group of 6 PCs. We had two players pick Scoundrel. It worked okay because one was more martial and luck focused while the other was more sneaky and social focused. We tweaked the lists of friends these PCs had so they didn’t know the same set of people. In future “big” games with the potential to double up on playbooks, I’d also consider different special items and different starting abilities (which could be from a different playbook altogether), with possibly more potential changes like custom playbooks. This is all to make characters feel unique and to have their own niche.
Vicing out hasn’t happened all that much in my game. I follow the rules for consequences and suggested resistance (reduce consequences by 2 levels). However, I think because there are so many players it’s hard to get to all of the PCs in the time we have and, as a result, they have less consequences to potentially resist. One time the Mystic viced out, but they have Center and so opted to have the spooky vision. The other time the Pilot viced and chose to play an NPC urbot that we made using the cohort rules from BitD. I think other NPCs that the crew encounters, as well as crew or personal contacts, could be a source of back-up PC inspiration.
My players are all new to Forged in the Dark, but they took to the idea to Resistance well. I still have to ask questions about how they go about doing what they’re doing fairly often, but I’d say they do a good job at handling more narrative responsibility. The big thing that still gets them is jumping right in to the job. They want to do a lot of legwork to get information before doing the job and still don’t really seem on board with the idea of starting in media res.
When I’ve split the group into two, I haven’t done two separate Engagement rolls. We just do one roll to see how the crew as a whole starts out. One example was when the crew was saving a damaged Starsmith vessel from Draxler’s Raiders. One group of PCs stormed the bridge while another group took the engine room. I just cut back and forth between the two groups whenever it felt right.