Yes I had a feeling they were coming
1) Yes, the units are divided into lvl 1-4, for making the randomized-production process easier. So what I call lvl 4 units are Dragons, Archons, Devils, etc
2) Sorry, it is not possible now. In order to speed up b4, we have decided to move "Scenario"-mode into b5. Which makes sense as we will build the tutorials as next step, and they will be using the Scenario-mode.
3) In normal mode, the city used as the players capital will be emptied at gamestart. So no troops or production will be saved there. In Scenario-mode (see 2) this will be possible. Not sure about extra Hero though as you would have to name him in the Editor also then, but its a good idea, will see what I can do.
4) Yes you can. You have a small button called "Map settings" on your right side. Click this one and you can set the teams. Layout is a bit broken though
Bugs:
1. Havent seen that one, sounds more like the site went down, or an Internetproblem. But will make some tests
2. Its a small color/layout issue at the moment for maps 150 tiles wide. Piranha will fix a bigger background image soon, and it should go away. Just dont finalize it yet, as you will then get that black border.
Good point, havent really tried to edit the top-right corner of such a big map. Will think of something