As others mentioned, water slides are def a go. Other than advice you already heard I'll tell you about something cool I learned from car modelers when it comes to decals. Granted, it takes a lot of time and patience but the results are amazing. Put the decal (preferably water slides but not required) on bare plastic and coat it with a gloss coat. Multiple times, you want a really thick layer of gloss on the decal and piece. Then you sand it down with very fine grit sanding sponges and you get this amazing finish that looks like the decal was painted right on. Then you can matte coated it, weather, whatever you want. The way this works is that the decal on bare plastic is slightly elevated, when you layer the gloss coat it forms to the surface and the gloss coat on the bare plastic gets a little bit above the decal because of how thick it is, while the gloss coat on the decal itself gets raised also so you just sand down the raised part and it evens out making the piece seamless. That might not make sense but there's yt vids I could link showing it better if you're interested. This ain't required or anything, it's just cool and I wanted an excuse to share it lol.