Easiest way is via the Shape Editor. Create a blendshape node on your destination mesh. Then select your intermediate mesh with extra joints or whatever, then right click in the shape editor, and "Add selection as target".
Try mass selecting the ones you wanna edit and hit F9. It will enter vertex/component mode for all selected objects. You should be able to modify them together once you do that.
By default the scale hotkey is set to Smart Scale. This will cycle the different scale modes. I always change it to Scale Object, that way it stays on whatever mode I've selected. Same thing for the Select hotkey.
yeah miss selections I find are by far the worst, it has lead me to always double check what I have selected real quick, a quick check can save a world of hurt.
Yep, those opened edges will cause problems when relaxing the entire thing. It's probably a bit cleaner to relax a selection of verts or faces. Turning on soft select helps when relaxing chunks like that.
One reason would be it thinks the poly is inverted. You can check with select > select inverted faces. Don't really know a fix besides just shifting the vert around till it stops tweaking.
Do you exit sub-object mode before adding the Unwrap modifier? You should. Sub-object selections are passed up the stack, so the upper modifiers are limited to just the selected bits.
I have such a Script on my homepage...it is quite simple to use...just select A first, then add all Ax to the selection and run the script. Modifiers will not be touched, so if A or Ax have those, the results will be References.
select one of the objects - eg: the legs convert to editable poly go to object properties and select "attach" then click on another object - eg: the feet now you should have only one object
but like I said if you select everything can you see the selection bounding box within the view or is it extending beyond that? Aka do you have some verts somewhere outside that view?