Welcome aboard. That's some really nice work you are doing so far. I'll post here some pictures I took of restored KA114 in 2014 though the details you are looking for may be hard to discern.
Here are some excerpts from various manuals I have that might help you:
Oxygen System. I believe that the economizers are on the roof of the bomb bay just forward of the front wing spar. The tubing is 1/4" copper. Feed comes from the bottles in the rear along the starboard side of the fuselage above the wing then down behind the Nav armour plate, piercing the roof of the bomb bay on the stbd side. I'm not very familiar with the run of the hoses from the economizers to the users, though the diagram below shows a long loop for the Nav and a short length for the pilot. The British manual diagrams are very hard to follow, in my opinion. The Canadian and Aussie ones are better, but the oxygen systems for the FB.26 and 40 will be quite different form yours.
The area behind the armour plate is a mess. The main things that you'll see are 3 torque tubes: throttle, prop pitch, and mixture. There are also fuel cocks with slow running cut-out switches that operate chains and cables running along the front spar to each engine. Tubing will consist of fuel tank venting, oil dilution, and pressure lines from engine vacuum pumps to the drop tanks via controls next to the Nav. The diagram below might help. It shows the wing detached from the fuselage. The "Area A" called out in this diagram refers to the Area A detail in the first diagram I posted above.
I don't have any photos of this area for an F.B. VI but lots for a B.35 which has some differences. Happy to help with specifics if you need them as it's a lot of detail for this post. I've been quite involved in these areas on a B.35 restoration and can lead you down the deepest rabbit hole you dare to go, depending on how much detail you want to show.
My 1/48 F.B. VI build might also help with other points, though I've not addressed all the details that a 1/32 kit would warrant.
