I saw this videowhich seems to have a work around for the external monitor issue. I have not got the 16 yet but hope this work around would help when using an external monitor. Two of my co workers are using the 16 with external monitors with out any issues.
I use my 16" with an external monitor most of the time and I don't hear the fans, so I'm one of the lucky owners. However, I noticed the laptop is noisy compared to my old 15" when I perform some tasks, like a long build in Xcode. Fans seems louder in the same setup (I had the external monitor even with my old 15")
I don't really mind, they don't run all the time so my MBP is usually quiet, but it is louder compared to the old one.