Re: Non-FIRST Motor Suggestions?
 

Update: I think I'm going to use ToughBoxes. AndyMark's 8" pneumatic wheels are out of stock. So are some of the parts that I could use to assemble them myself. How hard is concrete/asphalt on plaction wheels? If I go with plactions and TBs, would these hubs work?

Re: Non-FIRST Motor Suggestions?
 

If you're not on carpet, there's little reason to use treaded wheels over rubber wheels like the kit wheel. The hubs you linked work with any sprocket mount / bearing bore AM wheel.

Re: Non-FIRST Motor Suggestions?
 

Try 8" Colsons if you want a tough wheel that can be purchased easily and will handle concrete and asphault. The hubs can be purchased in a number of places like Vex and BaneBots. I also recommend the p60s with rs775s if you want to conserve space/weight and get similar performance. I used the same wheel diameter as you for this project linked below plus I was going through real simulated regolith with large jagged rocks in it. Before we had the fancy wheels with grousers we used Colsons as a prototype. The p60s will allow you to jam the wheel right onto the gearbox or it can accept most vexpro/AM products to get the right gearing.

https://www.youtube.com/watch?v=DaodHQC_MIo