I would go bigger tyre (at least on the front). A big tractor-like one could also help lift the front to compensate for the shorter forks (I'm speculating, you might like the fit but it's just the frame is corrected for up to 160mm and, IIRC, fox tend to be shorter a-c than other brands). Whatever, IMO big front tyres rock – maybe Bontrager Big Earl in 2.5 or (just trying at the mo') a WTB Weirwolf in same size.
I've never been bothered by stem brand / quality. Save the cash and buy whatever makes the bike fit best for least cost. But picking this and a tyre (to a lesser extent) will also depend on what rise your existing bars are. Otherwise it might end up a bit too chopper-ed.
I run an old (and everso slightly bent) Raceface XY post on mine. Like it, definitely needed it for personal fit (32" inside leg, 5'10", above average ape index ;-)) A Salsa Shaft would probably be OK too, but again, you can economise just like the stem. I'd rather save cash on these two and pimp up the chainset, personally.
I don't like V8s and would get something else. Like Kona Wah-Wahs but it's personal preference and whatever can be found in budget.
Sweet bike, hope you like it 😎