Crew Manning issue is a non issue!
There is no requirement for an FE on the P1. The jump seat seen occupied at RIAT had a 3rd pilot along for the long transit and there was a Chief Tech ( They call them FEs )along with his guys to look after the birds.
As for two extra guys down the back to handle stores, that is a legacy P3 thing.
That role was always fulfilled in The Kipper fleet by any member of the crew not doing anything and that includes Pilots when on transit to the Op area. Its not rocket science. Even AEOs could prep a buoy.
And another thing, The Kipper fleet managed quite well with internal stores launchers. P1 has belly stores. Luxury I tell you , luxury.
P1 and P8 crew requirements are exactly the same.