I am unable to reproduce either of your bugs on mac. I've never had firefox ignore a "force" reload in over 10 years of using the browser, and despite having the "dark" theme running, going to mozilla.com shows a white background just fine.
Yeah, because it only looks for GTK themes, not whatever theming engine windows and mac desktops have, which is further evidence of the absurdity of their wontfix explanation.
I am running nightly