Is it also ok to say "Did Vikings live in Denmark?"
Should be approved IMHO, report it.
Would there be any difference in using 'bor' here? I thought that 'bor' was more accurate for living somewhere as opposed to being alive
It doesn't really fit. At bo rather refers to a place of residence, like "do you have your house there"? But this sentence is more about spending your life in some place.
"Did the Vikings live in Denmark?"would be a better translation.
No. That would be "vikingerne".