As we now have some big Austrian freight yards in TSW like Salzburg Hbf, Wiener Neustadt and Wolfurt, it would be a nice gameplay experience to shunt in these yards. And for shunting, what would be better than a shunting locomotive that looks like a typical shunter when you think of one: the ÖBB 2070! (https://de.wikipedia.org/wiki/ÖBB_2070) 90 of them were built by MaK and their top speed is 100 kph. I don´t have exact informations if they are really on these routes, but this wouldn´t be the first fictional TSW moment I think (I could also use this loco really good on my route!)
Yes please! I love freight/shunting operations! There are about 20 of them here in my country too. They're mainly used, as said by OldVern, for shunting, convoys formation, small local freight shipments and rescue of faulty units. Voith wouldn't be bad either!
You forgot about the electric versions too ÖBB Verschrublok 1063 1064 1163. From the trio only 1163 and 1064 are Hump capable first one is actually inside Salzburg the second locomotive can be seen in Vienna Kledering