Have you looked into https://www.mactype.net/ to see if it would help with any of your font rendering issues?
However while looking around at a bug report to get MacType to work in Firefox [0] I came across a setting in Firefox's about:config [1] that can change the font rendering and that might help you out. Not sure about the history forking thing but there may be some Firefox extension to help with that.
[0] https://github.com/snowie2000/mactype/issues/673 [1] https://bugzilla.mozilla.org/show_bug.cgi?id=652141
It’s all a question of trade-offs of course