Ziggy has decided that, because of its support for LastPass and because it works with his themes better in its current configuration, Waterfox will be his main browser.
He will continue to support Pale Moon but I'm not sure to what extent - I will update the thread as developments occur.
As of 28 Aug 2017, current version of Lavafox that works with Pale Moon is v2.5.0., most recent version is 2.5.3. (will load in Pale Moon but causes the browser to explode when playing MP4 videos). I have suggested that he add some conditional statements into his theme for Pale Moon support so that he only needs to maintain a single version but I don't know how keen he will be on that idea.
It's very possible that Waterfox will soon succumb to the pressure and stop supporting XUL add-ons. When that happens, I'm sure Ziggy will repent and give full support to Pale Moon.
I really don't know what I could have done to make this swing differently but I did everything I could to help. I will continue to use every resource at my disposal to support and promote Pale Moon.