I ended up with the Mojo Audio Mystique EVO B4B 21 D/A Converter (with a couple of upgrades) and have been pleased with the sound. For various reasons, I am glad that I didn't go for any of the three DACs listed in my OP, although maybe the Terminator Plus could have worked for me.
No piece of audio equipment hits it out of the park in every area so it really comes down to finding gear that matches your sonic preferences, ergonomics (i.e., features/functions, display, size, and appearance), and budget. The main things I like about the EVO B4B are the rich, natural sounding tonal qualities, and the total absence of any digital thinness or stridency. The trade-off seems to be a leaning toward body vs. detail. I find I can listen to a wider range of music without fatigue because of that.
Benjamin doesn't sit still so he has come out with a new Mystique X DAC that will be offered at various levels and prices. I was a little disappointed by Mojo's abrupt change to move away from a model and style of DAC that was intended to be EVOlutionary, i.e., somewhat "futureproof" and upgradable. I suspect there were some supply and construction cost issues that forced the change. However, on the plus side, with Mojo you basically end up with a bespoke product that is built to a very high quality, using traditional designs to create the most realistic sounding music reproduction they know how to achieve. If he can offer the same sound quality at similar or lower prices with the new line then good for him.
If I were purchasing today, I would look hard at the Mojo Mystique X and the new Sonnet DAC, the Pasithea, both of which are due out soon. In addition to whatever upgrades the Pasithea offers over the Sonnet Morpheus, I probably wouldn't purchase either unless they improve on the hard to read display in the Morpheus. I have been spoiled by the display in my Hattor BIG preamp, which can be easily seen across the room.
The Merason DAC1 discussed by @starboard looks interesting and well-constructed but The Ear review had a couple of comments that seemed to move the DAC1 away from the type of sound I enjoy from the EVO B4B DAC:
"Merason takes a more black and white view and has voiced the DAC1 to be as revealing as possible and hang the consequences, whatever your source is producing that’s what you’ll hear." and "The tonal balance remained on the light side however and while this works beautifully with better recordings it can feel a bit uncomfortable with lesser ones,..."