MBR/SR was found in the wild pre garage sale. Multiple collectors had copies as well way before the stash came to light. It was out there to be had, and should remain included.

Nigtmare Busters will never be on the list as retail released as the SNES is no longer in production or sold at retail. Its aftermarket/homebrew/repro category

The 3 Mexico soccer games is really up to you. They have shaky information surrounding them to include in a US set, but they are NTSC, and could be included in a North/South American set.