Classic speakers to hunt down used

EV and Really true older Klipsch may be a rendundant suggestion. Klipsch used EV drivers on their oldest Heritage Series types and may have had them OEMed for the later ones. What surprises me is that the question mentions KLH, Advent, and AR all of which have a polite prentation then EV whichi s notoriously bright and then classic Infinity which used hard to Drive but forward sounding speakers some of which even had electrostatic drivers such as emits and emims which have great clarity. What "sound"style is your true objective.
I Second the IMF-Fried BTW. They made some great Transmission Lines. KEF was still more English sounding even though Bud Fried was working in their group. When Bud really had his say Fried (IMF) went in a different direction. But, you might want to check out some older KEF it seems like they might suit you.

What is the budget? My wife is a classical musician played professionaly , a violinist. She was quite taken with the corect timbre of a Consonance tube amp we ran across. And I personally like the VR1 bookshelf but its probbly too bright for you my wife insisted on the VR2s which are floor standers. If you have a small room the Omega sngle drivers and thier other speakers are magical with a small tube amp by SQ which is a brand distributed by Stephan Monte if you live near Philly audition them. Otherwise call Quest for Sound an A'gon dealer he will set you up with what you need. He carries inexpensive stuff as well as real High End but don't worry he is a super nice guy not snobby all what you can afford he'll have.
No affiliation Just a customer