made up my mind
 

Alright i made up my mind for rims.

mavic 519 rims
with aluminum spokes and brass nipples
shimano xt hubs
mavic mountain skewers.

Is this all i need to custom build wheels?

What do you think about this for my giant iguana?

The builder :D...

It is a sweet build...the iguana will be alot of fun with that wheelset :)

i can turn these into tubeless with stans kit right?

Would these be good for xc racing?

Anything is good for racing. I assume you are amateur level. 519's are a bit heavy for xc racing but at that level they should be fine. As far as I know Stans works with all rims...