But how do you plan to solve the issue that the free unity version wont offer access to the source code and the online player limit is 20 user at the same time?
I once looked into that myself, and only the pro versions, which cost a good amount of money, allow full access to the source + being able to have multiplayer over the amount of 20 players at a time.
Hope you dont use a ripped off version that got cracked thou. cause that would cause a lot of trouble.