My question is about users and licenses. I'm using personal ver. and not sure which version to buy. I think Pro but I want a user in New York to make the audio for me while I do the rest. How many computers and licenses do Pro come with?
Do you actually need Unity Pro? You aren't required to buy Unity Pro until you make $100,000 gross annual revenue. You can develop and sell projects with Unity Personal. To answer your question though you can install it to up to two computers but only one person at a time per license.
If the audio designer is a contractor, rather then an employee, then their is their responsibility to worry about licensing. It is also something they can probably do the job without Unity.