Yeah i could see that. bn don't get that big so i could def see this happening. You might want to look into getting a different bottom feeder like a hifin pleco or something else that'll get close to 16"
I don't think you will have problems adding the parrot but drop the pleco, once they hit 6" or so they are just pooping machines and with 2 oscars in your tank you will need all the "bio space" you can get.