And they have the fittings for the discharge and dampners, etc.
But I don' tknow what yu will do with the intake.
There are also companies that make inserts. Do a google on - kitchen vent insert - Now those arre designed for for over stove venting where you have your own finish surface. They come with lights and the grease filters. And with or without the fan.
Do some looking at those companies. Some of them might make an inlet grill with grease filters.