I flew longhaul with BA during that cabin strike in 2010 - from a passenger point of view, it was great. They pulled office staff, gave them basic safety training in evacuating an aircraft and put them on flights - it was wonderful because we gave up hot meals (they weren't qualified in using the galley ovens) and in return had super-enthusiastic cabin crew who were normally office staff (Mine was a project manager) who had a free holiday to Miami, loved every minute of it, and handed out booze like it was going out of fashion.
On the second point though, am not convinced they can train a fleet of pilots in cabin crew duties in two days.