Create a forum to communicate with customers and partners

Good afternoon.

To communicate with our customers and partners, we need to create a forum. Since it didnt work with forum engines before, I guess its easier to choose a solution on Vbulletin, Bbpress or similar systems. Well, or put together a solution on the fray.

The challenges that the required forum must address:
1) The ability to create themes and topics
2) The ability to highlight individual moderators for each forum thread, topic, or subs
3) The ability to open and close a reading of a particular thread, topic, or sub-topic to a particular user or group (such as a status sample)
4) The ability to manually add (registration) users to the forum: for example, by an invitation that is sent to an email. Or add the user themselves and he is automatically sent information with data to authorize it
5) The ability to integrate accounts with social networks - for simple further authorization on the resource
6) The ability to open and close comments without moderator confirmation
7) The ability to edit users: blacklists, assigning status, action restrictions, etc.

By design - something very simple, the main thing to adapt. Heres an example.

In addition: (but not necessarily) the integration of the forum with the payment system (e.g. Yandex.Money) to translate some of the forums themes into paid and open them to users only after they are paid.

Please write an approximate logic of actions to solve the problem and the approximate cost of developing such a platform (without additional development from the section "Additional" and with it).

Thank you.