Zaskar MTB frame: rigid fork, 1x10 gearing

I should have in my hands an older GT Zaskar 26" MTB frame come next week. It comes without a fork, so I need to buy a new one. I was thinking of giving the bike 1x9 or 1x10 gearing, but am at a loss when it comes to suitable bottom brackets and cranks.

1. My understanding is that the fork (rigid) should be around 420mm axle to crown. Is this correct?

2. What would be your suggestions when it comes derailleurs, shifters and crankset on such a frame in the 1x9 or 1x10 setup?

3. Info on decently priced disc brakes would be much appreciated as well.

The finished product will see some action, but it will be light compared to what the frame was meant to suffer. I know this is sacrilege, and for it I am sorry.

1. What would be your suggestions when it comes derailleurs, shifters and crankset on such a frame in the 1x9 or 1x10 setup?
   

Budget? My SRAM X7 10-speed kit (hub, derailleur, shifter, cassette) was under £150, very happy with it. Starting from a bare frame, ditch the X7 hub and get X9 Comp wheels, then add X7 2x10 GXP cranks and you've spent about £400. Ideally, bin the ramped and pinned chainrings and get a single speed specific one.

I had planned the end product would be around 1 200 euros or so, so I have around 1 000 euros still left. But this is the first time I am looking at MTB gear. No idea yet how expensive they are. So the budget might be way off.

The frame is a NOS 2007 Zaskar Team, which I have understood is the last model year of the aluminum era. I was hoping it could fit 650b wheels. Would you happen to know if this is the case? The bike will be used in a "friendly" environment: there will be roots, but not a lot of rocky terrain. So yes, I think I would have been better off buying a cyclocross frame, but I saw the Zaskar and wanted it.

Unlikely to fit 650B, they are only an inch bigger than 26" but there's not usually that much spare room at the back of MTB frames.

You should be able to finish it for ~€1000 with mid-range kit

€200 wheels
€100 tyres
€200 gears kit
€100 crankset
€200 brakes
€100 rigid fork
€100 bars/stem/seat post

That just leaves you short of saddle and pedals, but there's enough wiggle room in the list above to make up the gap, without dropping out of the usable gear into the worthless crap.

Mid-range is good.

Thanks, man!