Indeed, the rear pannier hook induce some wear on the rear mudguard stays but they are very strong, so its purely cosmetics (a part is now naked aluminum instead of black and polished).

Yes, the original easy wheels are small and thick, they prevent to mount some rear pannier. Their axle is an M6 bold like for the Brompton.

I mounted bigger 60mm, thinner third party easy wheels for Brompton bought on Amazon.de they allow to use Vaude Road Master Roll-it Waxed lightweight big rear pannier.