I've got an XD Whyte branded hub from a T130, is it possible to change this to HG?
Alternatively would it be ok to run an SRAM XD 11 sp cassette with shimano 11 speed chain (and chainring)?
The Whyte hub will probably be another brand with the Whyte logo on, for example the Hubs on cheap Specializeds are Formula hubs, best bet is contact Whyte Dealer or direct and get the part number.
Alternatively would it be ok to run an SRAM XD 11 sp cassette with shimano 11 speed chain (and chainring)?
Yes - I think this is quite common as the SRAM GX casette is a bit nicer than Shimano, plus to get the 10 cog. The shimano shifters are better for me, so I combine with shimano derailler. Have this set up on a couple of bike without issue.
The chains and chainrings are completely interchangable between brands so this will cause no issues that I can see.
I did this on a rear wheel from Whyte. They were very helpful when emailing although the new freehub cost fifty pounds.
This table might prove helpful.