I arrived at this the other way 'round from others - I'd already had high end 2 channel audio for many years and wanted a second system for music & HT without spending megabucks and getting complicated. I disliked virtually every HT receiver I'd heard - in fact I hadn't had a receiver of any kind since my vintage gear 25 years ago. I was strictly a 2 channel, finicky kinda audiogal.
I've been very happy with my Arcam AVR300 (powering Nola Minis) and the AVR350 is even better - I'll be trading up some day.
I would not recommend this approach with most typical HT receivers (I've had a couple Denons and others that are very easy to live without) but Arcam makes truly fine sounding, musical receivers. Treat the Arcam like a serious piece of kit with an after market power cord and decent wire and you will have a very satisfying musical experience and great HT sound. The Arcams are versatile too, offering bi-amping options and much else for audiophile tastes. And honestly, I love the simplicity of it all.
The Plinius and Cary are excellent integrateds, ones I've recommended to friends for 2 channel only listening. But I'm very comfortable with the Arcam gear for my all-in-one system.
If I were doing HT separates I would consider going with the Cary pre/pro and multichannel amps, surely one of the best kept secrets in HT/audio. But for a double duty system the Arcam is an outstanding choice.
Does my Arcam/Nola music/HT system outperform my high end separates? No, but it sounds pretty darned nice - my main system was an $16K+ system, with full rnage speakers carefully matched and highly synergetic with my electronics, cabling etc.
BTW, my musical tastes run primarily to lareg scale orchestral and choral works. I don't like hardness in the treble, congestion, lack of transparency etc. The Arcams don't suffer from these issues.
Go give the AVR350 a listen, compare with some integrateds, think about the logistics, make your choice and be happy.