I was thinking of including syncthing too since onionshare is not available in stretch for some mysterious reason. It has now been packaged for Debian. It supports socks proxies since v0.12 while the one in Debian is v0.14. Thanks to its relay support other nodes can act as conduits for those who need to connect over Tor. So it supports Tor AFAICT but I can test it with you if you wish.
I discovered foxyproxy doesn’t allow connections to clearnet sites when enabled. Instead of poking around its config files that look like a dogs breakfast, I decided to see if there is a workaround that eliminates the need for it in the first place and fortunately there is!
about:config -> search “network.proxy.no_proxies_on” -> Set boolean to ‘0’
I want to replace it across the wiki at some point.