Mellow speakers

"I'm here every Thursday" :-)

Mellow is good but you want accuracy ( hopefully) as well! This, of course, must fit into your price point(?)
you happen to be on the right track, however. You mentioned "old" kef 104's.
try to listen to or just BUY a pair of pre owned Spendor BC1, SP1 or Thiel Cs models. Modern wise, listen to a Harbeth or preferably the NEW Spendor designs . If you've never heard quads do yourself a favor ; as a re conditioned up to date pair of ESL 63 could possibly be in your price range! Also..... Take a good listen to the KEF Ls50... You may be shocked at what you will hear!

My bias has been exposed. I have owned the 2CE, Kestrel and just got a pair of the MMG's. I must like mellow speakers. Started to look for an amp/pre combo to upgrade the NAD receiver. Sounds decent, just want some more current. I can listen to these speakers all day long. The "digital" hardness tends to be tolerable. iPad through a Musical Fidelity V-DAC and I am a happy camper.

Dedalus Speakers
and Possiblly are Bryston which are borderline 
KEF coaxial a are a little forward
i heard Sonua Faber Olympic with primaluna and was very nice

I have the same sensitivity as you. I cannot stand that edginess because it hurts my head and ruins the musical illusion for me. I have spent years fixing it and i finally have a system that sounds amazing and more like real music than ever before. As you may have discovered each component can contribute to the problem or the solution. I have found there are detailed/harsh speakers (most audiophile speakers sound this way to me partly because i am sensitve to it, and partly because too much treble detail is what many audiophiles want, because they equate that with a more live and realistic sound. Then there are more balanced speakers, like vandersteen or old Proacs or Snell Type A1 (one of the most amazing speskers ever). But even they dont fully remove the edge, especially if you listen to recordings that are not perfect. This is all, of course, just my opinion! 
So, in answer to your question I will give you one unfailingly mellow speaker, the Spendor S100. It is incapable of sounding harsh and has a magic midrange. I found over time is was almost too dark, even for me... But it fits your bill. The other speaker is my current reference and will be for years: Quad esl-63. The quads are so musical, have the best midrange i have ever heard, and for some reason the way they reproduce treble is different that any speaker i have heard. They just seem to avoid that edge but still present treble energy is a convincing, real way. I bought a newly refurbished pair from Electroststic Solutions in Kansas City three years ago and they are amazing. I recently bought a pair of Audio Note AN-J spe speakers to possibly replace the quads amd after head to head listening the darned quads won again. I kind of wanted the Audio Notes to win because they mate better with my Shindo amp and look better too. But as wonderful as are the Audio Notes in terms of dynamics, tonal balance and musicality, they still have too much treble energy for me and sounded like hifi moreso than the magical Quads. I am afraid some of the dynamic speakers like vandy and quad may sound mellow to many people, but may not do enough to solve your need, if you are like me.

Anyway, feel free to send me a private message if you would like to talk more. I have thoughts on other components like DACs (I was thrilled to find out none-oversampling dacs like Audio Notes take away much of the digital edge, for example).
Stu