Look, I admire these guys as much as anyone. But Zombie Einstein himself would come back from the dead and smack you if he heard you claim that, e.g., Maxwell wasn't as smart as he was. Einstein figured out special relativity by staring at Maxwell's equations, after all.
I also look forward to your battle with Zombie Leibniz, who will be pretty pissed off at your one-sided exaltation of Newton. Although it's understandable that you didn't choose to anger Zombie Newton. Nobody does that and lives.
Having actually met the late Hans Bethe before he died, I assure you that his zombie will pack a mean slide rule. We're talking about a guy who discovered the main sequence, wrote the book on solid state physics, and served as the theoretical lead for the Manhattan project in his spare time.
Indeed, the list of dead scientists who were arguably as capable as Einstein is awfully long. You'd better start running. I hear that the tag team of Zombie Nicola Tesla and Zombie Michael Faraday is deadly even at long range, especially if you aren't properly grounded. And that's just the physicists... can you imagine the sheer size of Zombie Charles Darwin's Army of the Extinct?
The science in the book is 100% serious, too, and at the approximate level of an intro course in college. I faked it for three years as a biophysics postdoc with the help of that book. Admittedly, the molecular biologists chuckled at my understanding of their field, the way you would chuckle at a precocious four-year-old, but at least I had a vague idea of what I didn't know.
FFTW
(Feynman for the win)
The capacity of scientists (genius, output or however you define it) most probably follows a powerlaw with a lot of mediocre scientists, a few outstanding (Louis Pasteur, Henry Cavendish, Louis Maxwell) and only one true genius for every two centuries. Since we had a genius that broke through in 1905 we will statistically have to wait for quite a while for the next one.