List of favorite members

I would like that when a user makes a search among members of the community he can include some of them in his private list of favorite members, that he might consider later for friend requests or messages.

It would be like a "hotlist" of interesting members to contact later, without a connection.

In the profiles of the members there should be a button like "Add to list"
The list should be contained in a tab where the button changes to "Remove from list"

This list should not be obviously visible from other members.

It is possible?

Yes it's possible, but you're going to have to develop a plugin to do such a thing. The closest CB has is CB Connections.