That’s a nice looking plane. One thing to keep in mind is that small raising/lowering of wing, thrust line, and such does not have a very large effect at all. Often placement of things depends on other practical considerations. A mid wing might be more trouble to build if the design is using a one piece wing. Plug on wing panels are easy to locate anywhere. But one piece wings can be built lighter weight for the same strength. One piece wings attach to fuselages in the low or shoulder locations. Fuselage is lighter and stronger if the wing saddle is not cutting deeply into the side area. The plane in the link you gave no doubt has a relatively high thrust line because it makes the front styling look good. Inverted engine fully enclosed with good fuselage lines. Lowering the engine would make the cylinder stick out the bottom, or would require turning the engine sideways. Changes due to engine location really become significant for much larger changes like a pylon mounted engine. Basically all pattern or IMAC or 3D designs have the same general positioning.

I am not understanding your question about side area. Basically side area manipulation effects knife edge flight, yaw stability, and roll coupling with yaw. More side area forward makes it easier to maintain level flight in knife edge, but detracts from the others if not distributed well. Here again they have a need to keep the plane looking good too. Human nature is human nature. It's just a fact that planes that look great fly better, even if they might not handle quite as well. As long as a really good looking plane doesn't behave noticeably worse, then it's better. We all know how that goes.

Multiflyer