why not "is singing"?
Without any context, I would understand this Ukrainian sentence as "This choir sings...", but in an appropriate context it can also mean "This choir is singing..." I think, both should be accepted.
I would even go so far as to say that, without any context, "is singing" is just as reasonable.
"Chorus" should be ok
just curious, what would "native" be (native songs)? I thought narodni was native, or are they similar ideas/interchangeable.
"Native" in "native songs" is short for "native people." In Ukrainian it would be "пісні корінних народів." I would say that it is very close to "folk songs" in the meaning, but not completely interchangeable.
No, for songs this should be national / traditional songs.