I heard second hand, that the X-Men Adventures comic that was spun-off from the animated series presented the universe which predated 616, and from which Galan origionated. Is this true?

nope, X-Men Adventures is simply what it is: a comic book adaption of a cartoon based on a comic book. X-Men Adventures is just the X-Men cartoon in comic book form. And just as the X-Men cartoon was loosely based on the 616 universe but still an entirely separate continuity, same goes for the comic. So to answer your question, no it is not a predate to 616

From the Marvel Appendix
"In--of all places--The Adventures of the X-Men#12, the hierarchy of the Brothers (as higher than the Living Tribunal) is disputed. This is a somewhat interesting series, as I had initially just assumed it to be adaptations of the X-Men cartoon. I watched the first season or two, but didn't continue to follow it, so I can't confirm or deny this as being the case. However/Anyway, in this issue, the demons D'Spayre and the Dweller-in-Darkness instigate the destruction of the M'Kraan Crystal, which in turn destroys all reality. Phoenix harnesses all of the positive emotions of everyone in the universe and uses this energy to have the sentience of the universe join with Galan of Taa and allow him to survive the destruction of the universe, and to ultimately become Galactus in that Universe. So, the implication is that the events of that series (and possibly of the cartoon) took place in the universe before the current one.
At any rate, the relevance is here: During this conflict, the Living Tribunal is seen to be holding the Two Brothers in the palm of his hand, as he goes to consult with his "hooded, spectral ally" (clearly the Spectre). As the old universe is destroyed, the Tribunal releases the Brothers to "assume their pre-destined roles as architects of new realities."
So, while the Adventures of the X-Men is not quite official canon, the book was written by Ralph Macchio, with the assistance of Mike Carlin, indicating that both Marvel and DC were involved in this explanation. The Brothers are thus intermediary in power and authority between the Living Tribunal and Eternity (or their comparable counterparts in the DC Megaverse). However, each Brother tends has some authority and control over universes outside the standard Multiverse, but within the Megaverse, while the Living Tribunal has not been shown to have authority over worlds outside the Multiverse.
--Snood."
http://www.marvunapp.com/Appendix/brothers.htm

Many comic books like X-Men adventures that are adaptions of cartoons take events from the mainstream universe and apply them in that comic in an attempt to create their own continuity. Batman Adventures and JLU for example do the same thing. Many of the villains they've fought in the JLU comic did not appear in the cartoon, and were given the exact same origin from the comic. Jay Garrick even appears and makes reference to the Justice Society, which was never present in the cartoon. The Freedom Fighters as well. Slight references are made to events that have taken place outside of the animated continuity as well. This is just something that tends to happen when you have a comic based on a cartoon based on a comic. Continuity is thrown out the window, especially when said cartoon is no longer on the air. Again, if you're a big fan of the JLU cartoon, just read the JLU comic and see what I'm talking about. You'll notice the many differences in continuity. And one would think that this JLU comic is attempting to place itself in the current DC Universe as well based on some of the events taking place.