1. Do we get the PSD for the site's theme and also the vbulletin?

Yes
2. Is is possible to see the backend first? A demo admin account maybe?

I will set up a demo account for you
3. Is the vbulletin license owned? Will it be transferred to the buyer?

it is owned but expired I would just give the login credentials to the new buyer
4. I think the advertiser section isn't functioning properly, it doesn't let me login, and i don't see any payment options though the links appear on the sidebar, will this be fixed?

Your right I forgot to code the login and payment part and yes it will be fixed