The decks were armoured steel, with a 'non slip' surface. I think this was basically sand or similar mixed in with the coating, which seemed to be a greyish green.
As for figures, I don't know of any RN figures in 1/48th, but there are US deck crew which could be adapted/converted, especially if on the PTO/SEAC. Likewise, various other figures can be converted, some just by the paint colours used, and the Tamiya Panzer Service crew and other similar ones are ideal.
You might have to scratch-build a crane, or look at maybe adapting a 1/43rd scale die-cast crane, if a suitable sty,e can be found. There might even be something in the '0' Gauge model railway stuff, or maybe even from ship / maritime accessories.
The wing fold for the Avenger shouldn't be too difficult to cut and position, and I think I've seen a wing-fold mechanism kit, possibly in PE, possibly from Eduard. If not, then it would be tricky, but not too difficult, to scratch build.
Hope this helps.