Welcome to the site! I'll try to answer your questions in order.
1. Check the
Heaven forum for the character sheets thread if you need a basis for a text sheet. Otherwise, I don't think there's any definite preference towards any generation program or other method.
2. Each game has a built-in dice roller, which is found along the top toolbar in a game forum. Rolls made with it are visible to other players in the game unless you check the "secret roll" box, in which case the roll is only visible to you and the GM.
3. That really depends on the game, though in most DnD-style games I've seen, it uses something similar to the rules-as-written initiative system.
4. Again, really depends on the game. For DnD, pretty much the same numbers as you'd expect around a physical table, though some GMs like to accept a few more than they need to account for early-game player attrition.
5. All the time, unfortunately, but many games either recruit new players for dropped characters, or for new characters altogether, rather than shutting down entirely.
6. Same places you'd go for a face-to-face game, really. "Help a noob learn X system" GM ads are pretty common, so you might want to start with that.
7. Yes. Check the Help section for how to post images, and image-hosting etiquette. However, images aren't allowed on the public forums, and the code won't work if you try.
8. Sort of, though not like you'd expect from something like Roll20. The Heaven forum I mentioned earlier has a thread for ASCII maps, and you can always host a map image the way you would any other image.