Panorama stitch, sky replacement and colour grading

I need a series of raw images from a drone stitched together, sky replaced and graded. I need the resolution maintained as high as possible as this will be printed and displayed on a 20 foot wall.

Attached is the jpeg image the drone stitched together

This is the series of images - https://www.dropbox.com/sh/dvomi33x6w1z804/AAAP15mhqV_L8o1-wimjLRT6a?dl=0

If you're able to help please state cost and how quickly you can do this?

Many thanks,