Let’s see if I can hit a few of these.
1. Custom profile fields are no problem- the member management is actually shared with base EE- so your member settings in your current copy of EE? Will apply to the forums. That said- you can’t necessarily display all of the custom field data just anywhere- but it will show in their profile and such by default. Assuming you set it that way. Basically- the forum uses the same user settings as the rest of the site- with the ability to allow forum access rights based on member group.
2. It’s the forum in use here- so you can try checking the ‘New Topics’ link on this board- is that what you’re going for?
3. Sure- different skins aren’t a problem- it ships with several. You can see this in action here- go to the bottom of the page and flip out the skins under ‘Theme’. That said- it may/may not be easy to ‘import’ a format. Well- you can’t import one. But you can create your own. How hard it is will depend on how much you want to change things up.
4. No sub-forums (assuming I understand correctly). Pretty much what you see here is the standard ‘depth’ of nesting. If that makes sense.
5. Yes- though there isn’t a ‘switch’ to do it. But you can edit the templates, so if you want ads in a sidebar or such, you can just add them in when skinning. PHP can be turned on for the forum templates- so that’s an option, as is js. Or hard coded- but I don’t think many folks do it that way.
I’ll have to check re: the discount. Will get back on that one.