There will actually be two 3" ports on the front of the cabinet. They will be nothing more than just cut outs. Since it will be a true single driver speaker no crossover is required which makes the build that much easier.
As for speaker wire I have a bunch of 12ga laying around that I plan to use.
The finish is undecided, but will probably a veneer. It all depends on how much I like them.
I have some Raamat left over from my car that I will probably use then staple R13 insulation on the back and sides. Maybe some Deflex panels if I can find them locally.