OK i'm all weighed up, ive not included an random bolts and cables and grips, so the weight will be a bit on the light side, still lots of room for improvements.
Affordable changes are probably frame, saddle, seatpost. a nice wheelset would be great but can be pricey, especially as I'd like to keep a bit old school and run rim brakes and tubes, and I've guessed on the spokes/nips weight based on the full wheel weight less the hubs and rims (from google).
All this comes in at 9.835kg, weighed on kitchen scales, not digital!
I can probably shave around 1.5kg by changing to an ally frame, a charge saddle (£30), some wellgo mg1 pedals (£40ish?).
Get a 160 rotor. Or offer up the caliper and measure the gap to the post. It'll probably be 20mm so you need a 160 to 180 PM adaptor. I'd opt for a smaller 160mm rotor and may be able to help you out with one really soon...I'll drop you a PM. Smaller rotor will put less stress on the fork.
Have seen these before but didn't think they work well. The sd7 is only 150g a pair of levers, ms 150g for the vee I have fitted. Yeah the bb7 and rotor sits at about 450g! So it's still a big saving, but I think a good lightweight hydraulic is the order of the day.