As to removal of the "castle nut". I removed the handguard and secured the handguard mounting base in my bench vice and applied a bit of heat to the "castle nut" with a heat gun to soften up the factory applied thread locker compound. I was then able to gradually work the "castle nut" completely off (loosen then re-tighten, loosen a little further then re-tighten, repeat until it finally works loose).
I also went through the problem of the faux suppressor continually working loose. I initially bought the tool and tightened the snot out of the retainer but the faux suppressor continued to work loose. I eventually took mine off, cleaned off the threads, applied red Locktite and tightened it down with considerable force. That took care of the working loose issue. However I was less than impressed by the lackluster accuracy of my Micro compared to my 7.75in braced pistol. I finally decided to purchase the same KAK Industries, Micro Slimline Flash Can that CZ transition to on the new production Micros. Once I had the Flash Can installed I never had any issues with anything coming loose and my accuracy stabilized into acceptable groups.