loma,
Hadn't heard the part about the engine shutdown. That's a wrinkle I hadn't thought of. As for the reverser, each has its own accumulator which would have extended the buckets. However, the accumulator pressure for the reverser in the failed hyd system may have been depleted during landing rollout extend/stow operation.
I guess we don't know which hyd system originally failed ? For purposes of discussion only as all the facts aren't available, if the left system had failed originally and they shut down the right engine during taxi in, the right system would still have the electric aux pump to provide brake pressure through the right system.
We always shut down the right engine during taxi in so I'm assuming that if they also made a customary shut down, it would've been the right engine.
This is all a pretty interesting case.