if you rebuild the suspension to sm spec it should normally lower the bike a bit. I'm 5ft7 and about the same weight as you in full gear, when I had my suspension worked over it lowered the bike about an inch in seat height. combined with sm wheels that should lower the bike enough for you to be able to touch the ground.
as far as components go it comes down to budget and your own preference.
wheels: most go for an excel rim and talon hub combo, it's a prooven combination that's still affordable. I'd go for a 5 inch rear if you're planning on hitting the track, should fit on the wr if I recall correctly.
brakes: preference, I'm a huge fan of beringer setups. pricey stuff but you can get a complete kit with a matching caliper and MC for your bike in the colour you want.
motor and lights: I'll leave that to the guys with a little more experience with yammies but you'll have to change your final gearing, using the stock sprockets that were ment for enduro riding won't work all that well.
as far as the conversion goes you can piece the bike together yourself or just get a complete conversion kit like these: http://www.motostrano.com/sucoki.html