1: Never seen that on my setup, maybe somebody else knows this problem.
2: Yes, this simply does not work. I do hope this is improved in the upcoming release
3: Yes, this is a known bug, again I hope this is fixed in the next release.
The only way you can create new download tabs is by starting the monolith on the server, then close the monolith and re-start the daemon. The same goes for changing the priority of downloads.