Exactly. Owls are all about death and wisdom, and between Decidueye and Noctowl, it would seem we have both themes covered. The only reason the stilt owl hypothesis exists is because of people who desperately wanted to keep the "All Grass Starter Final Evos are based on pre-historic creatures" theory alive.
Oh, and the red around the eyes is likely due to influence from the brown wood owl, who also looks like it's wearing a hood: https://en.wikipedia.org/wiki/Strix_(genus)#/media/File:Brown_wood_owl_arp.jpg
Isn't Serperior just based on a snake though? And what is Chesnaught supposed to be based on?