Request for advice on office system

A small business needs an accounting / docketing system and I’m looking for advice how to do it.
What’s needed:

  1. small db of client names, job id, date1, date2. Could be .xls or anything else
  2. human-verify date2 for every new job using second person (eg. thru an email or web interface)
  3. generate goog calendar reminders from origin date after verification
  4. crosscheck dates in db with autogenerated .xml files (i know how to do this part)

basically #2 is the one I need help on as everything else is I blv. doable in python
so - send an email and look for a keyword? get user to click on something ? maybe links in the email, one for ‘ok’ and one for ‘not ok’? what do those links do?