- vertically-stacked wings (biplanes, triplanes) are common, but I've never seen 3 non-stacked wings. Not even the Nazis were doing that, which is a red flag for this project actually.
(I think it was France that passed a law that airplanes required at least 2 stacked wings around WW1, as monoplanes had too many structural failures at the time.)
- more wings mean more lift, but also more drag
- one advantage of more wings is that airports support only certain wing spans, so winglets or more wings is a work-around for that. (The result of winglets is mainly to effectively lengthen wing span.)
- very thin wings aid in penetrating the sound barier. This is a subsonic plane in terms of speed, but more accurately it's a transsonic plane (mixed subsonic and supersonic) over certain parts.
- I don't see the second engine, but if it has two, that's adequate for most oceanic operations because other small jets are allowed to do that, and ETOPS. (If ETOPS regulations apply, then engine reliability history is examined.)
- If the engines are too close together, then an uncontained engine explosion can destroy the other. This is fairly common for engines mounted near each other.)