I was also at Epcot extended hours the same night as lpandor on 12/14 and I can confirm the ride would have been available, but a cast member told us it was down for technical difficulties.
La Cantina de San Angel was also open when we passed it about an hour into extended hours.
I also agree we experienced a lot of ride downtimes last week, especially ROTR which was down all day 12/14 (our ILL$ was refunded by guest relations). When we did get to ride it on 12/16 it was in B mode and a lot of the ride seemed broken or turned off. That ride is really really not aging/wearing well!