The group admin options look better organized this way. Did you remove the site-admin options from there also? Note that in my opinion it wouldn't be a bad thing.
If you change the appearance for swa actions, please do so with some site-wide css (in fact, with some discussion we might adopt something like this for the base openacs sitewide CSS, define the classes even if we don't actually change the appearance by default, to make it easier for people to do so if they want)
Yes, that's the idea. Maybe, as simple as adding 2 new css classes to be attached to every admin link: acs-admin, lrn-admin (depending on what kind of link it was...)
The best site-wide css can be acs-subsite/www/resources/default-master.css
I have to try some options, and check if it works right.