When I left, Andreas was already lined up as CTO and Li Gong was still heavily involved in FirefoxOS -- I'd appointed Li COO but that got walked back, I think. Li stuck around for a year but left a year later (https://techcrunch.com/2015/04/15/mozilla-restructure/) to do Acadine. Andreas left in June of that year (2015). You'd have to ask them for details, if they are able to comment at all.
When I left, Andreas was already lined up as CTO and Li Gong was still heavily involved in FirefoxOS -- I'd appointed Li COO but that got walked back, I think. Li stuck around for a year but left a year later (https://techcrunch.com/2015/04/15/mozilla-restructure/) to do Acadine. Andreas left in June of that year (2015). You'd have to ask them for details, if they are able to comment at all.