The interior colours were the same as the MkI/III - nose and cockpit section black, remainder green-grey. Use the seat with the arm rests and armour head shield, the other one was the very late war and post war seat, although I've never seen one!
If you want a rough guide to the interior, have a look at my thread in the Group Builds 'Heavy Hitters' section, under Lancaster MkIII 'Oozlum Bird', might help a bit.
Love to see some pics of your progress, the MkII is way overlooked, and an interesting addition and conversion.