Does XCode 4 have keyboard shortcut for the two menu options: Edit > Find > Replace and Find Next / Previous?
If not, (1) why not, (2) how do I create them, and (3) which key combinations do you recommend for the shortcuts?
As for Find next/Find previous, you should be able to use standard Cmd-G and Cmd-Shift-G Mac shortcuts.
But the keyboard shortcut for Edit > Find > Replace doesn't seem to be provided by default. However, you can set up one if you go to XCode 4 Preferences (Cmd-,) and then click Key Bindings. There are options available for Replace, Replace All as well as Replace and Find Next.