Sounds like you have a nice-sized listening room. Personally, I wouldn't go with an active monitor. I'm not a fan of BASH amplifiers beyond usage for subs or desktop speakers. I like separate electronics, and for me the additional resolution is worth the price. (BTW, I have a Moscode 402B amp, CJ Classic preamp, and Harbeth Speakers in a man-cave).
I think BASH amps are essentially Class D amps. I have read that they are not always the best choice for higher frequencies. I don't know why or at what frequency these limitations begin to show.
It is noteworthy that Focal chose a Class AB for the 100W amp for the tweeters, but went with the 150W BASH for the Bass/Midrange drive. It would not surprise me if they considered the BASH amp an intelligent compromise to keep heat down. 250watts of Class AB can build some heat!
Which Harbeths do you have? I've been looking at and reading about them recently.
If Focal didn't make such good speakers across the board I would seriously wonder with that high ceiling of yours if they could adequately pressurize the room. But having heard their models in a couple of different showrooms I have no doubt you enjoyed their presentation.
My impression is the Solo6 Be's sound quite different from the Utopia 1028 Be's, but not in a bad way (to my ear). As full disclosure, I was not able to directly compare these two speakers, however, I did use my Paradigm S-2's as a common reference point.
At 113dB SPL (1 meter) rated output, the Focals will, indeed, pressurize my room more than I would care to experience! I off-load <80Hz to a pair of small subs, but the Focals put out plenty within their FR limitations.
