Though do also note that of these four, TD and RA1 were already made freeware years ago.

I realize. Intellectual property is an icky concept IMO but I know not everyone agrees

Which, in the immediate future, makes me wonder less about the things that are going to be done in code, and more about the creation of new, free, visual and audio resources that make this work. That seems like quite a noble pursuit.

Correct. The license (at least, the one I read for Red Alert) is GPLv3 with some additional stuff. The additional stuff is mostly about not using EA trademarks in your version or showing any connection to EA itself. So it appears that a clean room asset swap would be allowed as long as it includes the title screen.