I'm pretty sure they're releasing all the Justice League seasons, it's just a matter of when. My Justice League Season 1 on blu-ray arrived last night and I watched the first two eps. Looking forward to owning the rest of the seasons on Blu in the near future. Hopefully also the rest of the DC Animated Universe too on Blu (although the future seems a little muddled for Batman The Animated Series according to this thread:
https://forum.blu-ray.com/showthread.php?t=57824)