Sadly I didn't visit these places...yet. I'm planning on driving down to Wiesbaden again within the forseeable future (perhaps within the next 2 monts) to check out some of those residential areas in more detail.
Quick history lesson. The inscription reads
"Loyal to the fatherland I will remain until I die" which is also part of the Dutch national anthem. The Dukes of Nassau and the Dutch royal house are closely related.
City Hall: