the thing to look for is your speakers impedance not just sensitivity, if they are stable at 8 ohms you will have a lot of choices.
If your speakers are 94 db, unless you are in a small room you might want to consider something with 30-60 watts, depending on your listening habits.
My speakers are about 3 db more efficient than yours and I can run a 30 watt amplifier out of gas (but I sometimes listen at higher volume levels to stuff that can have a lot of bass). That 3 db is represents a doubling of the amplifier power, so to do the same thing on your speakers I would need 60 watts.
Living Voice are built for valves, sorry tubes and have a benign and flat impedence. I asked Kevin scott who builds them and he said they are built for tube amps, but not flea powered ones. If your favour jazz combos or solo singers, 8 watts will do, 18+ if its Mahler or heavy rock. So 15 watts as you describe, will be in the ballpark. I use a 22watt SET and it is perfect, but high powered SETs are expensive. As you say Art Audio, audio note would be good, the Leben amps are lovely, but the one I heard, a bit base light. If it was me, a VAC Avatar 2nd hand, if I really felt I deserve a present, a Vac Phi betta. I don't think I deserve a present by the way.
Any of the manufacturers you mention have amps suitable for your speakers.
If you are unfamiliar with tube amp topologies (single ended, push pull, triode, pentode etc.), I would suggest you speak to a retailer and audition a couple. If you can get them to let you try in your own home all the better.
Regards and good luck
I have heard Living Voice IBR-X driven by Shindo and it sounded GREAT. I am sure your other choices are just as good. Try to keep it above your 15wpc mark as suggested earlier.
Another amp you might want to consider is Consonance-Opera Cyber 211
($5500 new) or 300B PSEs' 15 watts . It was compered to famous Audio Note in Enjoy the music review.
Read the review
And nice review in 6moons (Blue Moon Award):
To sum it up. Tubes will work great with your speakers.
The KR Audio amplifiers aren't lush sounding. They aren't hard or brash either. I haven't heard the other amplifiers you have named ,but I can tell you the KR amps are EXTREMELY transparent. The bass from these units must be heard to be believed!They have been called the Krell of SETS..I agree 100%.
If you're looking for backgrounds as black as the abyss. This is the quietest amplifier I have ever experienced. I mean nothing from the speakers. Even with your ear an inch from the driver.
I would be careful with what preamp you match with one of these. Because if the preamp is noisy..your going to hear it.
These have to be one of the best kept secrets in audio. For the used prices they are a steal!
Your wallet may thank you even if your back doesn't.