I think I answered most, but not all, of my own questions. I see where in Shark's settings app it is possible to select FFD Show audio instead of MS default. So I renamed them back to original names and used Sharks app to stop the MS default and that worked fine.
So now I (finally) think I have things working pretty much the way I want. Sharks app really makes things a lot easier.
I still have some questions as to whether the MS default filters or those contained within FFD Show are considered superior and would love to hear some informed comments/opinions about that. My impression is that there is more control with FFD show, plus CoreAVC Pro, & AC3 Filter along with MPC-HC as the player with most internal filters disabled.
And so far I'm quite impressed with the quality I'm now getting on my laptop,with headphones and external monitor, especially with HD files.
Another question that I have is whether, if using only two speakers or headphones, it is better to set the audio config in Shark's settings app for 5.1 channels so all the channels stream separately into AC3 Filter and get mixed down to two channels in AC3 Filter. My impression is that this would be preferable because it allows for the possibility of adjusting each of the 5.1 levels individually in AC3 Filter before they are downmixed to 2 channel output. On the other hand, if one selects the two speaker config in Sharks settings app, the audio stream coming into AC3 Filter is already mixed down to 2 channels, so no easy separate level adjustment is possible in AC3 Filter if that configuration is chosen.
But since Shark's app specifically says to choose 2 speaker config if one is using two speakers, that's causing me some confusion. Perhaps there is some other reason I'm not aware of for setting it up the way that apparently is "recommended" in Shark's settings app. For now, I'm keeping it at 5.1 unless I run into issues with this configuration.