pretty sure it just stays on your account, you just can't upload new blacklisted files
"Share stuff you create for the good of others. Open source your designs and code. Try to use the web for making other people's lives better. You have the power to reach millions of people - use it!" - Abigail Pain, https://www.akpain.net/blog/the-modern-web-sucks/.
I wanted to originally have a separate portfolio website on sr.ht sites, to have things more abstracted, but its still probably going to be linkable back to me. Alternatively, I was thinking of having separate identities for these two sites, which again, may limit what I can show to potential employers.
I personally wouldn't because some of what's on my site isn't something I'd want an employer to see at all, but that's me. I'll be making a separate professional portfolio under a different name if I ever need one, personally. You could also try hiding the content on the current site, but that depends on whether you expect something like curl or wget to be used to get the source for the site.
As much as possible, yes. The alt color schemes are the only thing that needs it, and I have light/dark CSS to fall back on the user's device preference if JS is disabled. Any pages that need a color scheme can be reached with the URL/sitemap alone as well, and any JS-formatted bits will still show something without JS.