Creating Email Sending Rules in WebForm in Drupal 7
See webform_rules:


  Did you ever want to react on webform submission using rules but
  couldn't find the proper event? Webform Rules makes it possible to
  catch webform submissions by rules and do whatever you'd like to do
  with it (meaning: do whatever rules let you do with it).


It should let you perform most of the logic you've outlined here.