2) I assume this is because it expects an image to be uploaded, and I think this might have already been fixed. Had these in Notepad, was planning to recheck, but my rechecking would take hours, and yours takes minutes :)

4) 14: ReferenceError: folder_list is not defined
http://localhost/cms/themes/admin/templates_cached/EN/catalogues.js?1461151677

This occurs when trying to change the order of a field.

A lot mixed in here...

1- Hold down ctrl on Windows (which I just tested). On Mac it is the option key.
2- Related to a bug when CRON isn't set up, fixed earlier. Re-tested, including testing an image field (based on your separate note).
3- I've attached an issue that relates to this. As you can see there's a lot of harmonisation and improvement I want to make, but that's a big job. As a compromise I have made it so the help button for the delete checkbox does say what will happen. I acknowledge the potential for horror if a user didn't expect this, but I do think if they're going around deleting stuff it isn't unexpected for contents of what is being deleted to go too - so I hope users at least will pause enough to read that description. I've voted for the big improvement issue myself, hopefully when we're freed up to do more development, we can encourage some people to sponsor it.
4- Fixed.

Set as 'no change required', just to represent the mixed-bag nature of this. Some changes were made.