A lot of questions here, but I will try to answer them one at a time.
Price for our existing subwoofers: We would argue that the sound quality is higher than a lot of the competition due to both superior drivers, superior amplifiers and DSP, as well as very well built cabinet. It would of course be up to the customer whether they are willing to pay for that. And if you compare with other subwoofers aiming for a similar market like the new KEF KC62 (which is cheaper but also relatively expensive), we also provide double the output even from our smallest subwoofer. This is of course also a matter of which market you are in. If you have 10,000USD speakers, you don't pair it with a 500USD subwoofer. I also understand that if you have 1,000USD speakers, you probably don't buy our subwoofers. That's perfectly fine.
Price for a package: This is yet to be determined exactly. But you're likely talking minimum ~8,000USD for a pair of these speakers combined with our smallest Inkognito subwoofer. We have the 10D coming up too, so a killer combination would be the SBS.1 combined with 2x 10D. That would set you back ~12,000USD. This is not cheap. It also does not sound cheap. We've had pretty competent people here to listen to our prototypes, and speakers like the B&W 800D and the Kef Blade 2 have been mentioned in discussions regarding the sound stage and overall impression. A reporter from a Norwegian hifi magazine has also been here. When discussing SBS.1 + one 10D (which is what we listened to), he simply could not come up with a pair of speakers within the price range that sounded anything like it. Also remember that you will not need a power amplifier (which would typically set you back several thousand USD in this price bracket), you could connect this directly to a streamer, and have a complete system.
Integrating with existing subwoofers: The speakers are "high-passed" out of the box, as they will have a -3dB point at 80-90hz. So yes you would be able to pair them with an existing subwoofer. If you don't have existing room calibration or crossover-capabilities in your amplifier, it will be even easier than with a "normal" speakers, since you can utilize your subwoofer at a larger part of the frequency range.
Signal path: There's a DSP both in the subwoofers and the speakers, and you have access to manual 9-band PEQ in both the subwoofer and in each individual speaker for room calibration. You would connect this like you would a normal sub, and a power amplifier. The subwoofers support High-level, RCA and XLR. The speakers support RCA, XLR and also Optical/Coaxial for digital input, but you may have some trouble finding streamers/preamps with variable level digital outputs. Yes, if you use analog inputs (which is probably the most common use case), you would get AD/DA, but this has been proven to be transparent even when doing 7-8 conversions in a row so this is not a practical problem with modern DACs (if it ever was). Yes, MiniDSP SHD would be a good match to this system. Currently our prototype setup is simply connected to a Yamaha WXC-50, and using manual room calibration through the built-in EQ in the speakers and subwoofers. Works like a charm. Many would probably opt for a more expensive streamer, but even this setup works extremely well, even for its total price.
WISA/Wireless: We will not support wireless out of the box.
Hope this clears up some of your questions, please do not hesitate to follow-up.