Thanks MikeJ - That additional information is helpful...
Based on the options you listed, I would recommend you go with System #2. Here's why:
1. I wouldn't go with System #3, because in-wall speakers come with too many compromises when it comes to sound quality. I would only go with this system if it was your only option.
2. It's tough for me to say, but given your circumstances I would also pass on System #3. The ESLs are great, and sound fantastic, but they really need certain things in order to sound their best.
- First off, I'm firmly in the camp that says electrostatic speakers need external amps as opposed to receivers. I know there are more than a few people who run ESLs with receivers and are happy, but my experiences tell me different. Each time I've heard those kind of setups, the music was thin and the sound stuck to the speakers (very narrow soundstage). At the very least, listen to an ESL/Feature set-up running from an AVR before you pull the trigger. Trust YOUR ears.
- ESLs also have particular needs when it comes to placement. At the barest of minimums, they need to be place 2.5 feet off the back wall. This is to take advantage of the rear-firing sound wave of the electrostatic panel. Ideally, you would like to speakers to placed 4 feet from the back wall. This kind of placement is tough to do in a shared space. Much easier in a dedicated room.
System #2 will work well with the receiver you have and offers you a bit more flexibility in speaker placement. While the sound quality might not be on par with ESLs, the folded tweeter design does a great job at stereo imaging and will give you plenty of audio enjoyment.
As far as subs go, I wouldn't go with Dynamo 700. It's too small to provide deep movie bass for your 2600 cu ft room. If you can manage it space-wise, I would look at Rythmik Audio's LV12 sub. It's got a larger driver and its servo- controlled, which will keep you bass articulate and not boomy. If you still want to stick with ML for you sub, you might want to hunt for a ML Grotto i, which is also servo-controlled. It's discontinued, but I still see them once in a while online.
Again - these are just my thoughts based on what I listened to in the past. As roberto always says - trust your ears!!!