The Essenes and the Zadokites were two different groups. Early on, during the discovery of the DSS, the scrolls were attributed to the Essenes. This stuck; and it seems that many scholars have difficulty letting go of this rumor. The Essenes were in Ein Gedi.
They also had a quarter in the city of Jerusalem as well didn't they?
Yes, we must remember who took over the discovery and much of it was to make sure their 'agenda' wasn't compromised.
Was King David a zodokite? ...giving him the shewbread to eat straight out of the Holy Temple, indicates more than moral physical support
Actually it was the Mishkan, the Temple wasn't build yet.
As far as King Davids genealogy, it is interesting to note that His roots are not entirely pure from Judah.
His GGGrandfather Salmon married a Canaanite prostitute, Rahab.
They in turn produced, Boaz 'the kinsman redeemer' and he married a widow named Ruth who was from Moab.
Their child, David's Grandfather, Obed produced Jesse, Davids father.
Now Jesse is interesting as
some believe that his wife's' name was 'Nahash' for those reading this name means 'serpent'.
So as we can see, David comes from a long line of mixed soup.
As for the shewbread, the priest told David that he would give it to them, only if he and the men had not recently had sex.
5 And David answered the priest, and said unto him, Of a truth women have been kept from us about these three days, since I came out, and the vessels of the young men are holy, and the bread is in a manner common, yea, though it were sanctified this day in the vessel.
Strange wording, especially mentioning the three days .
However we see another odd statement from the priest.
6 So the priest gave him hallowed bread: for there was no bread there but the shewbread, that was taken from before the LORD, to put hot bread in the day when it was taken away.
The Shew bread, or 'Bread of the presence' was changed out on Friday so there would be fresh bread there on the Sabbath.
This statement by the priest could be trying to give reference to the day David was there, or it could be that he gave it to them because it was 'old', that they were ready to change out the week old bread for the fresh 'hot ' bread.