I do think the memory issue is related to firefox as it only does happen when it is open. But it is such a random/rare issue that it is not a problem. Just annoying when it does happen, then all it takes is restarting firefox.
Not sure what happened as it just started working today, as for more AV scans I have ran so many since the issue started I bet I have at the least spent 12 or more hours waiting for them to finish and only thing that has been found were those 2 programs (same one just 2 different drives) that were not even installed. Plus some adware/spyware that malwarebytes removed.
As for the occasional memory issue, it is rare and while annoying having good internet speed I can catch back up to on whatever I was streaming fairly quick. That is the only time it happens also, so probably a issue with the cache firefox or flashplayer uses not clearing after moving to a different video.