I don't know about the feet part, I know rotties are very sensitive about having their feet touched, thus hating nail clipping time (which is why they always advise getting your puppy used to that from day 1 so they are accustomed to it)...
Rotties don't do well in the heat, so I always walk after the sun goes down in the summer time, and keep the walks shorter, sometimes just down to the end of the street and back (I have an older girl)
I've found if you don't have a big pool already, just getting them a plastic kiddie pool is a fun time for them, and a great way to cool off after walks, or just play around in.
I've actually seen some people put a doggie type sham on the dogs, when it is super hot, and its really effective at keeping them cool.