Answering the questions that I can answer, in order:
Blackout - I tended to put the blanking plate in my window when I was using the H2S for fixing, or RV's on Fishpool, otherwise I left it out. I vaguely remember there was a curtain but I can't ever remember using it. The rear crew area was far less claustrophobic than the Vulcan and I suspect nowhere near as dark.
Annie's hatch I'll leave to RFCC - it was an unpressurised compartment well aft on the port side of the fuselage and gave access to various bits of equipment that crew chiefs understood - all I know is it was handy for putting all your kit in when going overseas!
Dont put too much faith in my info on JPT's - you really need someone like Victor Pilot to put you right on that aspect, and in any case what I said may only have applied to Mk1/1a.
Astro was practised reasonably regularly, but when crossing the Atlantic it was done for real as we had no long range navaids (eg LORAN), were well out of H2S radar range of any land and the Green Satin was unreliable over water. On those occasions the crew chief must have slid his seat well forward to allow access to the periscopic sextant but I just can't picture it?
Regarding the paint schemes, the two Mk 1a's you mention would both have carried white anti-flash and grey green camo in turn, only the K2 would have had the desert camo. Always wished I'd flown in a white B1 -what a super aircraft that looked - by far the prettiest of all the V bombers of any type or mark.
No idea about any of the weapons you mention - the only thing we carried which went bang was the Verey pistol which was occasionally used to facilitate RVs and was great fun to fire!
That covers what I can answer from above.
Roger so far? ...over!