I’m not sure how completing the FCC projects translates into an ability to code for non-profits. Wouldn’t it be better to use (pared-down versions of) old non-profit projects as FCC projects, so you’d get practice at things you’re likely to be doing once you’re coding for non-profits?
Do you realise how much of a jump it is for most people to go from the Tribute Page to the portfolio, let alone a Dungeon Crawler built in React or a full Pintrest Clone.
If you get to the point where you can do all the projects, you can work through issues well enough to code up any* web app.
(* fancy machine-learning / blockchain / augmented reality / webVR projects not included)
Not sure if you saw this already but FCC changed the way members will be working on non profit projects. freeCodeCamp's new certificates - here's how we're rolling them out
So in my opinion working through the projects and challenges on FCC is probably one of the best ways to be able to contribute to the non profit projects that FCC is supporting.