Hi friend and welcome to MorphOS world, I'm sorry to can't answer to all your questions, but I try someones,
1.) I don't know.
2.) There is a easy way clicking with the right mouse button and in the menu choosing the information now opens a window with the default icon you can drag and drop your new icon and click in save, now the file appears with the icon, there is any icon utility to make the same thing but only I know and use one from Amiga 68k.
3.) Here in http://www.morphos-storage.net/ there are always the last software for MorphOS.
4.) Yes using the Ambient preferences.
5.) I don't know.
6.) I don't know.
7.) There are several but a interesting is this: http://www.warmup-asso.fr even this site has a android app for mobile devices with information the newest MorphOS software and news.
8.) I don't know.
9.) I don't know.

And thats is all, I hope help you in anything.