I am 99% sure this isn't DCAU. It's not the first time they've used the old voice cast for some of the DTV movies. Besides which, aside from homages, I don't think Timm has actually expressed interest in revisiting the DCAU.
Though I'm sure the folks at Watchtower Database will make some convoluted video about JL vs The Fatal Five being connected
I jest, I jest
Speaking of, we were gonna drop a speculation video on Sunday and then the casting news came out last night, so we decided to edit and put it out before they dropped anything more on us