Database schema design implementation feedback
Ok, given there are no restrictions on the behavior of someone asking a question, we can forgo a lot of trouble migrating the UserId through the data model.
I don't think you're too far from the mark, just some unnecessary Id columns that aren't providing value.
This should satisfy the requirements as you've described them:

Some notes:

I changed Like to Vote since that gives more flexibility.
If we do need to restrict the behavior of the person asking the question, we would need to use their UserId in the primary key, or change the primary key from QuestionId to something like (UserId,AskDatetime) or (UserId,QuestionNumber).
If you do choose to allow more than one answer per question, you would change the primary key of Answer to (QuestionId,UserId) (although you might want to rename UserId to something like AnswererUserId).  To denote an answer as accepted, you'd need to create an AcceptedAnswer table where QuestionId is the primary key and AcceptedAnswer would have the relation to LiveStream.
The one 'oopsie' that could occur with this data model is logging that the presenter (the person who answered the question) also attended their own Livestream.  If you were doing attendee counts, you'd need to query Answer to make sure you don't count them.  If that is very mission critical, you'd move the UserId of the answerer to the primary key of Answer and migrate that through LiveStream to LiveStreamAttendee and place a check constraint to ensure the UserId of the attendee is not the UserId of the answerer.