(1) I found this video issue with MC 20 posted earlier this year, and I hope MC/Mac has caught up in this regard. I play mostly MKV and MP4 video, but still have a few AVIs around
http://yabb.jriver.com/interact/index.php?topic=95628.0 ...
Video support for Mac is vastly improved now. I haven't used it with an external display yet, but on the Mac's screen, it's rock solid for just about every video format I've tried. See my post here for some details:
http://yabb.jriver.com/interact/index.php?topic=99998.0- (a) connect to my Yamaha AVR via HDMI and still use a Thunder port (and adapter) to connect to a DVI monitor(?)
Again, I have no experience with external monitors (or TVs) with my Macs, other than playing with it a few years ago. Seemed to work just fine back then, but I wasn't using MC back then. Anyway, the new Mac mini has HDMI on board, so that should be no problem. It's also got 2x Thunderbolt connectors. You can buy an inexpensive mini display port to DVI convertor, which will plug right into one of the Thunderbolt ports, so again, you should be good to go.
- (b) connect to 2 USB3 external drives
Certainly. I'm using multiple external USB drives with my MBP. Currently using them with an adapter because mine is old enough to not have USB3 built in. With the adapter, they work very very well, and multiple drives is no problem at all.
Sorry I don't have a lot of direct experience with your questions and/or setup, but I thought I could add a little to the conversation.
Thanks,
Brian.