Can anyone, irrespective of whether a moderator, create a coding challenge?

Answer 1

Yes, anyone can create assignments(coding challenges), here is the guide for it https://www.sololearn.com/learn/11393/?ref=app
Good luck

Answer 2

Yes but they must approve.

(e.g, assignment https://www.sololearn.com/learn/4943/),

Answer 3

Thank you