also if a reply in a topic has already been marked as answer (I guess there can be multiple replies marked as answers in the same topic), when admin visits it again they still see the "mark as answer" under the reply that has the answer tick (I'd expect that to write "unmark as answer" for users that have that right [e.g. admin and forum owner etc.])

This is released by the 4.7 version so we can close this topic.

Regards