Bandwidth confusion regarding Japanese flip phones in the US.

So after doing some surface-level research about how to get one of these Japanese flip phones working in the US (I'm on the East Coast), I've found that the bands under your provider in your area need to be supported by the phone itself or something. For T-Mobile, I have bands 2,12, and 66 at the cell tower near my house. I've heard that it is ideal if not necessary to have at least 2-3 matching bands with what the phone requires. The charts I've seen that show the band compatability normally are compatible with b2 and b4 when it comes to T-mobile. But I've seen multiple times on these posts that b12 also works from user experience, but on the chart b12 isn't circled to signify that it is supported with whatever phone it may be. Being that I need at least 2 matching bands and I only have the b2, knowing for sure if b12 will also work will kick start the process of me buying one of these. So I guess I'm wondering if b12 is compatible with any of these phones like the Ky-42c or 902kc/903kc, Keitai Digno 4, etc, and can be confirmed. Sorry if that didn't make sense but I tried lol.