What is the threading of the microphone mount? And can it be attached to a boom arm?
The thread size of the mount is standard 5/8". To attach the mic onto a scissor arm stand with a 3/8" threading, you need to screw the 3/8" to 5/8" adapter to the arm stand. Such an adapter is usually pre-attached to the boom arm. The installation demo is as below (from 1:45 to 1:51).
Which shock mount and pop filter fit on the K669B mic?
Most shock mounts on the market are designed for microphones without a volume control. You can get a shock mount or a pop filter from FIFINE microphone accessories.