Thank you, guys.
I really like how the animated people look like here, but as you said, all have the same speed and they bump into other instances and into other obstacles. This is nearly impossible to avoid, since you can't really preview the animated objects without repopulating each frame, which is quite inconvenient to say the least.
And there are 51 populations with animated people! So, in this case I don't really care. It would be nice to have the walkers behave more natural, but it's just not possible at the moment. As far as I know!
Right now I'm rendering frame 63 of the HD animation. The quality is good, no flicker. It's going to take some more time, since, as I wrote, TG is refusing to work from time to time. It's not crashing, it's just because 16GB RAM isn't really enough for this...