https://smartgit.userecho.com/topics/64-add-take-both-merge-option/

It already does.

I reckon with "review window" you mean the "Changes" view. Currently, it changes its content on selection change in the "Files" view. What do you expect the "Changes" view to do after you have changed something and select a different file? IMHO a selection change should not show a confirmation dialog.

Please try Ctrl+Space.

A branch is not part of a commit in Git, but just a named pointer to a commit. The colors are just that - colors for making the log easier to read - they don't refer to any specific branch.

I don't understand the argument "especially if you work in a team that uses a lot of feature branches and Pull Requests". Could you please describe your work-flow?

Fixed since 17.1 preview 4.

Just select both commits (where the branches point to) in the Log and you will see the diff in the Files view.

Do I understand you correctly, that you want to add the same repository (= directory) to different repository groups? That won't be possible because we maintain a set of directories.