Need suggestions please.

  I have a requirement where

   1) If order State is set to submitted, it should be submitted to AX

   2) If order is inserted with Order State as submitted, it shout be submitted to AX

   3) If a case status is changed to specific value then Order should be submitted to AX.

So to implement this which is the best way, Plugin or workflow?

Can I use three steps in single plugin?