Is it possible to let multiple users from one console play at once/together? Or is this limited to one active account per console?
I take it you’re planning on dumping your Wii U’s console-uniques and sending them to your friends? We simply cannot recommend you do this
In the event one of them nets a console ban, you and everyone you send your uniques to will be unable to access Pretendo Network until, best case, the offending user appeals the console ban or, worst case, you buy another Wii U
Another thing would also be the potential for your friend, or friends, leaking your console-uniques, meaning that someone with the means could start playing online using your console and also can get your entire console banned if they break the rules
A third concern would be piracy, if your friend(s) don’t own the console, chances are they do not own the games they will be playing, even if they use a dump you made, it’d still be piracy as they don’t own it, this also extends to you lending them games and they make dumps or them owning games in some fashion but illegally downloading another copy
The best option for you and your friends to play Wii U together would be to just buy Wii Us and the games you want to play and dump the games and online files for use on Cemu
TL;DR We would not recommend you do this for various reasons, including and not limited to console bans that may arise from you or your friends’ actions