Proxy sites aren't the best for applying for Adsense with. The Google Adsense program requires 'quality content' (their words) and free domains are also not recommended. They ask for aged sites at least 6 months old, and unique content that has value for the visitor. They have numerous help pages and blog posts that state this. Apparently one way to do it is to start a blog and add to it regularly, even a blogger blog will do. You might also be invited to take part in the Adsense program from YouTube videos you upload. Once you have your Adsense account then you can put the code on any website you have, as long as it complies with their (strict) requirements, including proxy sites.
As for promoting your proxies you'd be better to wait until you can monetize properly. Adsense on the home page and Adversal on the proxified pages. Adsense isn't allowed on proxified pages so you can't use it or your account will be banned. If you promote them now you won't earn any money from them and by the time you get Adsense (if you do) then your proxies will be way down any lists submitted to and most likely already blocked by the filter companies, so won't get enough traffic to make any money from. You could use another ad network to start with if you're impatient to get going, you don't want to be providing a free service and getting nothing in return, you'll still have costs so you should try to recoup some of them at least.