Thomas,

If your DC ductwork will live near the HVAC I'd plan it now so that none of the pipe crosses. Or run DC down one wall with branches running within joists.

I'll second Jim's recommendation to keep the jointer and planer together. In my shop I have a 'triangle' of the jointer, planer, and big bandsaw. Infeed and outfeed for all three point at open spaces between other machines/benches.

Really love your project!