Ziemowit,
What a wonderful project. A wonderful mix of old technology (when was the organ built?) and new technology. Excellent choice of sample set. I think that considering the size of the original instrument, you selected a sample set coming from a similar size instrument.
The integration of the new controls is very well done, keeping the "old feel/look". Are you using the wet or dry version of the Freiberg?
Superb work!
François