Pine should be OK. Be sure to give it a primer coat or two and two or three coats of oil based paint so that the boards won't absorb water. Make the paint color a bright color like blaze orange or sunlight yellow so you and other boats can see them.
Not sure what the stuff is called but we use boards that a friend made out of the composite material used as wood in homebuilding. It's in white and come in all sizes at HD or Lowes. It's being used now for trim, etc. It won't ever rot, hard as a rock yet can be drilled in to, Srcews, etc. and it's light.
If you want to pull big baits and not limit your usage to clam to moderate weather days, there’s no replacement for displacement. Those light weight plastic boards maybe good on your arms but they will boob around like a wine cork on rough days unless you use a triple. I’ve seem people add steel bars to the bottom of the boards to get a better bite in the water but you then defeat the purpose of using a light weight material in the first place. The set I use was made from 2x10s and are 36” long and have never had to pull them due to weather. They are not the lightest things in the world but then again I’m only carrying them from the cabin to the back of the boat before throwing them overboard.