1. The sprites are colored in GB pallet of 4 shades of gray as well as each color pallet the GBC offers to original gameboy games. The sprites are laid in sheets by their pallets and contain additional information for further pallet info for added authenticity (if purchased, refer to the included readme that has a section on sprite pallets in gbc)
2. You are free to edit these however you would like and use them in any way you like, royaltee free and attribution free. The only thing is that the sprites must be a part of some work (i.e. Don't take the pack and sell/redistribute it like it was your own.) Commercial works are fine, in any form of media you choose.
Thank you for replying. I am really interested to purchase this and https://luckycassette.itch.io/lucky-bestiary. However, my only mode of payment is Bitcoin and it seem that your asset cannot be purchased with Bitcoin. It would be good if you could kindly enable Bitcoin payment.