If you have a Standard account on UNA.IO and view another member and see Access denied (because their Profile is not public) then there is no Follow only Add Friend.

It's standard behaviour. To be able to follow member, the member should allow this, since user don't have separate privacy specifically to allow to disallow following, then the privacy for "following" is the same as for visibility. So if profile is public, the everyone can follow member, if profile is visible for friends only then only friends can follow this profile. I think it's logically correct.

Second I don't see the point of being able to unfollow/follow someone you are friends with (unfollow/follow doesn't effect Friends status as you have to unfriend separately)??

It isn't exactly clear, could you please describe the problem in more details and how to reproduce it ?