but Nevado de Colima should be accessible, correct?
I belive so, but I haven't been to Mexico since the 90's. I haven't heard of the Nevado being closed though, and there isn't anything that indicates so on the SP page.
btw, are axe/crampons needed for this in Nov usually?
Usually, the only mountains that need ice axe and crampons in the entire country are Izta, Orizaba, and formerly Popo. Late November is also the dry season.
Other than the two I mentioned, I'm not familiar with any of the other peaks in the area. I know Baja California has some nice peaks, but I haven't been out that way.