Converting in-house CMS to WP

I am looking to WP to provide some equivalent functionality to an in-house written CMS as follows;

1, Public user can register and add entry
2, Registered user can upload images to their entry
3, Registered user can preview their entry
4, Registered user pays for their entry, it then becomes ‘public’
5, Registered user can amend their entry at any time
6, Public user can see all paid for entries without registration
7, Public user has to register as ‘enquirer’ to send registered user an inquiry

At no time would I want any registered user to see the back-end dashboard of WP

Any feedback on the above would be gratefully received. I understand there are many points which I am sure I will break-out into many further questions, but I need to know if this is possible.

Regards and thanks
Pete