Now open a second port to enable rpc, here I will use port 2222.
That's only required if you want to remote control the wallet, right? Seems safer to turn it off.
You know I'm not actually sure on this, 8bit party or Drays or someone could answer. I thought it was necessary if you in order to run an mn, but this may not be the case... Every mn guide I've ever seen include the rpc port. test it maybe until someone has an answer.
You do not need RPC port open, unless you want to remote control your masternode via some automated tools. In fact, better to keep it closed (or accessible only from localhost/127.0.0.1), to decrease the chance of somebody breaking your RPC password and stealing your coins.