Wow, what an incredible build!
Have you thought about some expanding foam for inside the PVC pipes? Maybe you can slip some wooden dowels in with it to add some rigidity. Some of it is also made to be a pretty strong adhesive and it's obviously light weight. The rotocast resin is a good idea for strength too, though it may be hard to spin some of the parts...
Maybe I skipped over that part, but is that console surface only made of the formica? If so, I really doubt it will take much button pushing and playing. Maybe a piece of sheet metal, at least some flashing, for behind the buttons?
I love the greeblies you have added so far, too. I am surprised there aren't more droid parts! Seems like we in the R2 group are always seeing droid parts in other areas of the SW universe. Like the Volvo dash panels, we see: The reading lights from R2s dome, some of the greeblies from his leg/shoulder areas (we call them the buttons and hydros) and restraining bolts, which look a lot like some of the pipe pieces you have assembled in some of these pics. Many of the R2 and Threepio parts (well, okay all of them) exist in resin and are fairly inexpensive.
Please LMK if you know of any that you need and I will look in my garage. I should have a few extra R2 pieces.
Also, have you considered doing a repair for that broken switch that still shows the broken formica (but is strengthened underneath?) The Falcon had as many years under her belt as anything in the SW universe, meaning it was used, cracked, broken and dirty. Maybe there has been a decision to make this more pristine (that I missed) but I thought I would mention it. I would expect to see some wear and tear around the edges, at least.
Great work and very fast! I love the PVC guns. I might have to build something like that for my kid's swingset/fort...