Welcome
sea monkey ..this would be a very nice model.......& I am shooting from the hip

@ a scale of 1:24, would make the model about 1500mm long
She is a deep draft hull, so a displacement could be some 12 to 14 kg
The 1/2 section GA also confirms she has a FWD hold for cargo, and an AFT area under the deck for Crew?..... listed as a sleeping room for
Kaptain, then on the Port side a sleeping room for
Machinarist ..engineer ??...
She may have been built in Scotland, however the Ships Drawings has German text
So to answer your questions as best..
A. the paddle shaft axis does appear to be above deck level. In the real vessel the paddle shaft would have been covered with a wooden how height cover or bridge, suitable for walking over, however on a model, it would be an advantage to has the paddle shaft exposed for a visual advantage
B. Your assumption of a WC was normal, however on many vessels, you may have had 2 x WC on one side then a Galley & storeroom on the opposite side. In the ERA of these vessels, ther was no BLACK waste water storage, all matter went overboard
C. Your assumptions are pretty well on line
D. ....there is no question of or @ D
E. Yes
F. these 4 x planked/slatted areas are termed as Sponsons [FWD & AFT, on Port & Stdb sides]. In most sea states, the AFT Sponsons are covered with splashed water from the Paddlewheel wash. They are Slatted for quick drainage of water
Lastly, yes....... chains from the wheel house to deck level on Port & Stdb sides........then longitudinal rods tucked beside the Bulwarks to the stern where these rods were joined chains to connect to the steering quadrant
Hope this is of some assistance.....keep us posted
Derek