Ok, this will seem a bit complicated, but once you figure out all the ins and outs, it helps a lot.
Short answer, text editing to remove the sequence.
1. Back up your file first. Text editing a file can be ruined by just 1 character.
2. Right click you .an8 project file, open with, choose notepad.
3. Ctrl+F search for the fist few characters of the sequence name.
4. Delete everything from sequence { "sequence name" to the first } that is all the way to the left including both those lines.
5. Save and open in Anim8or. If you were careful and did it right, you will have physically removed the sequence from the file itself. If it won't open, delete the one you just modified, back up again, and try again if you want to.
Hope this helps ya.
Second problem, no clue, sorry.