The end of year release will be a little closer to the end of the year, if not a little over that estimate! And it'll be paid, as it's essentially an early release of the full game, rather than a demo!
Out of curiousity, upon release of the early-access version (paid version); will the future updates/patches be part of that paid package? or will it be a seperate cost later on?
If you buy the early access release you'll be entitled to all of the future updates for free as the rest of the game is built upon and finished, since this is treated as a sort of soft launch of the whole game.