Hi Steve,
So as long your understanding links you to God, the divine or any path to discovery I don’t think there’s necessarily a fix answer to this. That being said I understand synchronicity as a certain level of awareness and communion with God. It is an unspoken language with more than one meaning. I understand dejavu(something I seem to experience all the time) as less special and more a playing of the mind. Like being conscious of a similar event previously stored in the banks of ones subconscious. Just my opinion on the matter.
For me deja vu is much more then experiencing a similar moment but as it has been explained to me by other friends and by myself: it is THE EXPERIENCE of having been in a particular time and place before. Not a SIMILAR time and place.