Shortcut to rename multiple files in the Finder
Solution 1:
As I don't need so many files renamed simultaneously I simply added this few shortcuts for different numbers
To do this open Preferences > Keyboard > App Shortcuts > + and add Finder with exact Rename 2 Items... menu title and so on)
There is more complex solution via automator, which I don't like it as it resets Rename Menu state each time you open it.