the 100/90-19 will match the rim and with H speed index it can be used without any technical issues.
In Germany we have to go to TÜV /MOT and get that tire size noted in the papers, otherwise it is treated as illegal ;-(
LTD/CSR rear tire will stay at 130/90-16.
The rim accepts up to 150/80-16 but there is not enough clearance to swing arm (except Beltdrive swing arm ;-)), chain guard, chain itself (that causes most problems during operation) and the brake drum holder.
Bs can use a 120/90-18 at the rear.
I like the BT45 as well.
No idea where to get white wall tires.
From my knowledge no major tire manufacturer offers that in that size.