Looking for input on Legacy Audio speakers purchase.

Yes calbre plus wavelet

Plus 1 on the wavelet plus Calibre above. With the right power the Calibre can fill a pretty big space. I really don't see myself changing speakers down the road, just hopefully adding a Wavelet and I'll be set.

My room is 16x24 and I wouldn't say it is too "small". Then again, I have a preference for floor standing speakers as I prefer their presence as opposed to bookshelf speakers. An 8" woofer just doesn't do it for me. Comparing apples to oranges as it depends on what you like and want. The Aeris is totally different IMHO.

I don't want a bookshelf speaker. This will be my last speaker. Just concerned Aeris is too big for 15x21 room. Another reason considering Focus SE because I don't think is too big for 15x21. 

You couldn't go wrong with either one I would suppose. The Focus is a fine speaker and I am sure the design and driver changes over the years since I had my old pair, have really improved them. You have copious amount of power to drive them like they should be. Maybe I'm a bit naive but I'm not getting this "too big for the room" thing....... If I had a 10x10 room I would say any large floor-stander might be too big in an overkill way. The reality is that the Focus and Aeris aren't much different in size or potential SPL. The difference to me lies in the design. I think the Aeris is a different animal with the 8" midrange and open baffle. All one could do is try to demo both of them and decide, considering all your personal factors, which is for you. I also would reiterate that the Wavelet is the real deal, tamed my room immensely since my options on room treatments were nonexistent due to WAF. Good luck on your jorney and happy listening!