Improved anchor point editing

(This applies to anchor points for Face Mask, Face Stretch, and everywhere else anchor points are used.)

I understand that drag-select defaults to only active anchor points. But this is not convenient when one wants to activate and move a number of anchor points all at once. Maybe a modifier (like shift) could say "hey I want to select ALL anchor points, even the non-active ones" and an additional one (like alt-select) could say "hey I want to select only the non-active anchor points".

I'd also like to be able to invert the anchor point selection, and maybe save selections to re-load later (a la Photoshop).

Furthermore, I think unmodified click-and-drag should only be able to edit/move anchor points that are already active. At the moment it is far too easy to accidentally activate inactive anchor points. I propose that ctrl-click (and optionally drag, to edit if desired) should activate anchor points, which once activated can then be moved with unmodified click-and-drag.

When dragging an anchor point, I would like to be able to hold a modifier key (ctrl, for example) to "snap" to the X or Y axis (depending on which it seems I'm trying to move in).

I noticed that in Face Stretch, moving an anchor point displaces surrounding/connected anchor points. I'd like to be able to turn that on and off both when editing anchor points for Face Stretch as well as for Face Mask. Perhaps a modifier (alt, for example) could toggle between the user's current toggle setting and the opposite.

This is probably way advanced but I would not mind being able to enable/disable the proportional editing thing (described in previous paragraph) for certain anchor point groups (think Blender vertex groups) --or at least constrain it to certain axes or to a certain connection distance (pixel-based distance and/or node distance --would be great to be able to choose between and configure both).