Nadal, Yes. He won't take the AO-final trashing well. He is even more of a favorite for RG 2019 now. If he can make the final of AO, he has enough oomph left for 'la douzaine'.
As to Roger, I just don't see how he can sneak one, let alone two, slam. The landscape has changed yet again. He blew last year's SW19. He blew AO this year. He had a good shot at both. He noted that the conditions at this year's AO are already much slower/heavier/bouncier/whatever than last year. Bautista Agut makes his first slam Quarters after taking out Cilic. Poulle makes his first slam SF after taking out Coric and Raonic? Pouille never made it past the first round at AO. So Roger is a contender at only SW19 going forward. He has to make it to SF without choking, not easy anymore. He then has to go through one or both of ND/RN.