

I did the non-repeatable quests. It is possible that those four quests (or rather the first one) give you tickets in any case, whether you are grouped or not, and only the other activities (defeating a boss and so on) require a group/companion? I guess I will see that tomorrow.
edit: I got the tickets on completion of the first non-repeatable quest, from the big khajiit. I was not grouped or had a companion active. Coming to think of it, that's probably why I did not get tickets for the delve boss you need to kill during this quest. So yes, you probably need companions active or be in a group. No idea why I got the tickets from the khajiit, then. Perhaps an oversight.