Full range speaker recommendation

Sonus Faber Lumina Vs should work well in that space.

If you want to keep a form factor similar to the ATCs, Spendor Classic 2/3s will be fuller sounding than the ATC's.

Lastly, as a total alternative, it's worth giving consideration to Magnepan (Magneplanars) - they might lack a bit of punch on classic rock but they are superb speakers.

Recently added a pair of Focal Aria 936 and am quite smitten. If possible to audition somewhere, may be worth a listen. 

I recently went through a similar price range search and ended up with Klipsch Forte 4s. I would have happily bought the Cornwalls but they were a bit too big. For full sounding speakers I also loved the Focal Arias, was very intrigued by the Paradigm Founders, and I also really like the Kef R series. Lots of great choices, good luck!

Magnepan 3.7i on the used market with your subs should sound fantastic. I play mostly rock and some jazz on mine along with a bit of classical and have enjoyed every minute. Also check out Philharmonic audio Dennis McDonald makes some excellent speakers.

You're listening on the long wall and your width is 15 feet or so. That's kind of a short distance, relatively. I'd think you'd need a speaker that can pull off a full range sound in that configuration. With that in mind, 

I've been interested lately in Eminent: http://www.eminent-tech.com/index.html?fwd=LFT8.html

These speakers sounded good when I heard them. They're big and heavy but you might  consider Legacy https://legacyaudio.com/products/view/signature-se

Devores might be good, too.