Sorry, Late response; new member. Still relevant questions as the 105 is remains in production.
First, the 105 DOES possess ample "lip sync" adjustment via the remote/on-screen menus.
Second, I can attest that its "digital" volume works superbly when direct-connected into my five-channel power amp. it has the typical output of a typical preamp, but better S/N, separation, etc., than anything in its price range.
I actually purchased the 105 over the 103 to take advantage of the 105's pre/pro abilities in my digital-to-analog "purest" system. Frankly, I find most AVR's over the top and excessive in options, though if you have more sources and take advantage of a full-blown AVR's features, fine.
The 105 is very well made and the included remote, though not ultra fashionable, is also solid and the accessed on-screen menus are simple and effective. IMO, you get 95-100% of the usefulness of an AVR and a higher-quality interface and build than most products in the 105's price range. It has its own torrid transformer, as well, along with TWO jig-quality DAC's. Runs a bit warm, though.
My recommendation: Try out the meaning at your dealer and see if you agree that the 105 is simply a stunning hybrid performer. There are some revealing reviews and the OPPO site is full of info and a manual download also available.
I see no dedicated pre/pro in my future. I just hope OPPO stays on track and delivers the 105 update in the future. Truly a great product.