No idea how compatibility issues.
I *guess* that designer, having released Key West NAS several months after our KEYW, might have checked for it and hopefully took care of it or, at least, provide with some instructions.
Assuming there are compatibility issues, they might be fixed if you remove two .BGL from our scenery package with *KQNX in their name ( data and exclude ), this will surely work if you bought our KEYW on FSDT store or on Simmarket.
If you bought it on the MS Marketplace, there might be a problem, since it's not possible to selectively remove .BGLs from a scenery, since they are compacted in a single encrypted file. Maybe, in this case, rearranging the scenery order the Content.xml file might work.