AN-J or AN-E with Meishu

Fred, in my opinion, your (almost) square room is the most limiting factor. If you are going to remain in that room I would advise keeping the AN-Ks, because they will pump the least amount of energy into the room.

If you were going to move into the larger rectangular room, either the AN-J or the AN-E should work. As you now, these speakers both share the same driver complement (basically) but differ in cabinet dimensions and upgrade options. They sound alike, but also quite different. Personally I would probably lean towards the Js, but that;s just me.

There is an inexpensive way to test which will sound better: find a pair each of used Snell J/IIs and E/IIs in good shape and try them out. While these are not the same as the AN speakers, they are the speakers that Audio Note based the AN-series on and they share similar sonic qualities; just not as much of it as the better (and more expensive) AN speakers. But this test shouldn't cost you more than $500 USD and would be money well spent if it guides you in the right direction. I imagine that you would be able to resell the Snells for what you paid for them or very close.

Good luck

Fred, construction of the room is just as important as the dimensions, wall materials, floor, windows, furnishings, etc. all come into play irrespective of size. I've done a lot of near field installations of large speakers in small, difficult rooms like yours with excellent results and there have been a couple of occasions that rooms with seemingly ideal dimensions turned out to be nightmares because of their construction. More information is needed for any kind of suggestion, even then without being there physically it will be all guess work, but it might be enough to get you going with your setup.

If your aim is specifically better soundstage and image the key factors are speaker positioning and low frequencies. Bass is the foundation that will give you the solid 3d imaging. Bass is also the hardest thing to get right in almost every room, even large ones.I don't know your level of experience with speaker positioning and system installation, that plays into what you should buy. I'm not familiar enough with any of AN speakers to make a recommendation but I would always pick the one with best bass reproduction capabilities.

Your thoughts and suggestions are very useful at this stage. I have limited knowledge of acoustics and greatly appreciate your help. I experimented a bit moving some furniture around yesterday and agree that this makes a big difference on the acoustics and the overall quality of the experience. I need a few reflection/diffuser panels on the walls (I'm probably going with Vicoustic) and wonder about about your advice on bass and soundstage. Do bass traps "only" reduce unwanted reflections or can they also help create better imaging/soundstage?