I just checked on my 5diii. And it's really good news. 31 of the 41 cross type points remain active even at 600mm. That is better than a typical f5.6 lens which usually give only 21 active cross types.
With the tamy 150-600 and the 5diii all 61 AF points work. 31 of 41 remain cross type points. Specifically, the Cross types points active will be all points at center column, 1st columns from center and 3rd column from center. The two outer columns remain regular focus points. None will be double cross types, however.
That's great. I wonder how it would be paired with 7Dmk2. 5DIII is way out of my budget.