As I answered to your previous question, you do not need to forward any ports for the p2p interface. This is the interface nodes use to send each other data, such as blocks. transactions and peerlists. Other nodes can sync with you fine without router port forwarding because when you initiate an outbound connection to a peer, it is kept open, thus data can be both sent and received. More important for p2p traffic is how many connected peers you allow and how much bandwidth you allow. Settings already explained.
Wallets however need to talk to nodes over the RPC interface. Thus, if you want to help wallet users who don't run their own node, you can forward the RPC port to your RPC listening port (in your example this is port 18081). This you do on your router, normally under a section named "port mapping" or similar. You will be filling in details to tell your router to "make requests coming to port 18081 go to computer your.local.ip port 18081"