Fox definitely makes a float that would work with those arms.
Don't bother with any gimmicky axle extendo junk. just get a Gforce axle or find a really nice used one.
The 28 pwks are a solid choice. There are intake and filter combos out there to keep things spaced nicely.
The FMF's would be more then fine for what you're doing.
$75 radiator is pretty common. For now the quality has been up to snuff. The radiator shroud might be a touch tight but it all fits.
Alba just put out nerfs with heel guards. Also XFR has a new model. My favorites are the AC pro pegs. Easily found used.
Stems and risors can be found used or even from a few of the site sponsors.
Porting, hands down the best thing to do to a motor. But it requires a total package to reallly take advantage. Just discuss with a few builders when you are ready. They will go over your intended use, expected output, fuel type, what mods you already have and would need, etc.