Sorry Scott, I originally did not see the links.
I cannot vouch for the quality of this seller, but yes, that is the right caliper to use.
Remove the gold coloured slider frame and the silver colored park brake cap and bolt it to the solid adapter I made up with the park brake cap screws. I made the adapter out of 1/4" steel but 1/4" aluminum or thinner steel would work.
The caliper is now rigid and the earlier sliding disk will work fine with it.
The Blaster/Banshee/Warrior Master cylinder will work, I have used them, but has a large diameter cylinder and takes a lot of toe pressure to lock the rear disk. I had better luck with a master cylinder for Chinese 50cc/90cc ATV/Quad.
Also note the tab welded onto the lever was shortened up considerably and M/C angled toward the lever to improve leverage.
I don't think the 2003+ lever is a a bolt on. I modded the older lever in all cases.