You can give other users access to your tournament, so you can manage it together.
You can grant specific sections per manager (e.g. only schedule and results, not the settings).
Yes. You add someone using the email address they already have an UwTornooi account with. If they do not have one yet, have them create one for free with that address first — after that you can add them.
Yes. When adding someone you choose which rights they get, and you can release specific sections per manager. That way you can give access to the schedule and the results without letting them touch your tournament settings.