When the G6 releases for RRO and there are some shunting services in Hagen, make the DB BR 363 also substitute into the services from the G6 that are in Hagen. Maybe you can also do it the other way around (G6 sub into RSN BR363 services around Hagen).
Yes, the 363, 204, and G6 should be seen on more routes than the one they came with! It would add a lot of value for the player
The G6 locomotive could work on the RSN at the power plant. There would be a lot of work for her to move coal wagons.