For the wood to metal Cascamite and polyurethane are first thoughts. But the plastics thing is a real wild card, plastic can be notoriously difficult to bond to other materials. Some don't glue well even with epoxy: you can actually use these plastics as dams or as a mixing palette, it'll peel right off after curing.
Can't say it'll work with all the plastics you want to use but there is this stuff called CT1, a sealant and construction adhesive that's amazing apparently, and it comes in a wide range of colours including clear. It won't break the bank if you want to try a tube and it can be bought on Amazon.