Hi Edison, your steps are good to have it working. However, instead of using step #2, you can keep the uplink connected and prepare the CLI on both switches and apply at same time. Then, just add the port to the LAG.
Regarding the use of active/standby, you can accomplish that by using the feature "Software Controlled Redundant Port". Please see the article below:
https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-configure-software-controlled-redun...
Port-based algorithm will use ingress port to decide which egress port to use. Since its dynamic, you won't be able to control that.
Instead of using Active/Standby I would recommend you to use LAG for sharing (L3_L4 algorithm).