Bob, are you using the 32 bit or 64 bit Win 10? Note that you must match the version of Kontakt 5 Player to the OS, i.e. 32 or 64 bit.

Question #2 - Does Kontakt 5 player come with a 32 bit version? If yes and you are using the 64bit BiaB the 32 bit Kontakt player will not show up. Also if Kontakt is a VST3 BiaB will not see it.

As far as your 5 HDs, take one of them and put all of your VSTs on it. That would make your life a lot easier. Put all of the 32 bit VSTs in a folder like C:/Program Files (32)/VST, your 64 bit VSTi2s in C/Program Files/VST, and your VST3s in C/Program Files/Common Files/VST3. This works for me. YMMV

Note that you could use a wrapper to convert the the Kontakt 5 Player to either 32 to 64 bit or 64 to 32 bit but in the past I have found them to be problematic. With everything going to 64 bit wrappers are no longer needed.

Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware