1) I'd have to say this depends entirely on the game and your marketing abilities. C2 games can reach numerous platforms (though not very well at this point in time) so you might expect to see more possibilities regarding the monetization of your game than you would with other game makers.
2) Eh?
3) There are no image editor tools as of yet, so you will have to import your finished graphics. You can import all of your frames and animate in the editor though, and there are some nifty features to go along with it.
4)You can set an object's opacity to its current opacity and then adjust it as you want e.g.
+Every Tick
-Set object's opacity to Self.opacity-60*dt
This will have the object slowly fade out. There's also a fade behavior but I've never used it.
5)Yes, using webstorage and other plugins, but I haven't messed with them much. Save data for browser games is not great from what I've seen.
6)Select a layer in the layout editor, then check out the properties at the left side.
7) To my knowledge the free edition only limits layers, events, and some other more trivial things.
Finally, be sure to check out the manual and take your time looking around the forums!