Always 6 cabin crew-unless it was a check flight-where you might (annually on average) be assessed by a training steward/ess.
3 in First class and 3 in the back. The Chief Steward (always male in those days) would normally help out at the back during a meal service etc
During my time- time there were only First class and economy sections-nothing in between. Some of the 436s were in all economy config (174Y)and would normally be used on the North Atlantic affinity group charters etc to Toronto/New York etc-although did do one trip to Varna (Bulgaria)-which may have been an Airtours sub charter?-but cant recall the details??
None of the 707s had a seperate lounge at the front that I ever remember seeing. Crew rest area-didnt exist as such and you would sit on a bar box in the rear galley or the normal double jump seat by the rear exits.