Most Helpful Guy
Absolutely do nothing that you wouldn't normally do. This isn't about showing off or showing him up but instead it's about being happy and moving on. People can tell when someone is trying to project and it doesn't look good.
Most Helpful Girl
Just don't post anything. If you post a bunch of happy stuff, it'll just seem like you're trying to prove to everyone that you're unaffected by your ex's relationship. I'm glad you're doing better:)