Yes, I believe this is possible...Either with an HDMI->DVI adapter, or possibly just an HDMI cable if the hookup with the display will be via HDMI, not sure though.
Yes, I have a 27" TB Display plugged into the TB port on the mini and a Dell monitor using an HDMI->DVI cable.
To address your second point, you can not use the TB port on the TB monitor to drive a second monitor unless it's also a TB monitor. I tried a MiniDisplay-> DVI (or HDMI for that matter) and it didn't work. I talked with AppleCare and they said the TB port on the monitor doesn't support MiniDisplay output. This sort of sucked because I actually wanted to run three monitors.
Yes, I have a 27" TB Display plugged into the TB port on the mini and a Dell monitor using an HDMI->DVI cable.
To address your second point, you can not use the TB port on the TB monitor to drive a second monitor unless it's also a TB monitor. I tried a MiniDisplay-> DVI (or HDMI for that matter) and it didn't work. I talked with AppleCare and they said the TB port on the monitor doesn't support MiniDisplay output. This sort of sucked because I actually wanted to run three monitors.