I normally grind then mix . Like said above this was to cure the meat first , before grinding .I've seen it done both ways, but I'd put myself in the camp that would mix the seasonings into the cubed meat, then grind.
If I do chicken sausage , I mix the seasoning in first , before grinding . Because I do it over a couple days , and like to have the salt on the chicken cubes overnight . Just to help keep it safe .