It's super hard to meaningfully measure success for virtually anything we do. In many ways we are the catalyst for things the community does (or would do) anyway, we can just dedicate time and effort to things that others mostly can't and, in doing so, hopefully fight fights for them in code and process so that when they *do* try and use new APIs, features, technologies, or processes that they're not alone. Basically it's kind of like a combo of R&amp;D and applied sciences in my bald head. Generally, though, the community mostly does a phenomenal job of that anyway, although sometimes a little too well (I'm looking at you, eleventy billion MVC frameworks!)

Many of the things on your list are exactly right inasmuch as they're all things most of us do, although I would add one: technical credibility. If you're not actually building things, how can you be relevant? Empathy helps a lot, and it also helps other developers to know that a) you experience at least some of their day-to-day issues and b) that when you implement something well that they can benefit from it (via OSS etc). 

Anyway, to the point, which is to say measuring success... I guess I have a question mark over the whole thing in general. A thought experiment: you could persuade 1,000 people that something is a good idea, but not one of them may be able to do anything about it because of other constraints on their time or focus. Equally, you may influence 1 person who then goes on to make a game-changing technology or product. You want the latter, and just measuring numbers doesn't tell you that you were successful. Often, though, it can be a decent proxy. Ultimately, I just try to do my best, and hope that whatever I create will help and inspire others. Not the most solid metric ever devised, but there we go! I do, of course, try and track stats and metrics for whatever I product, and I try and tie them back to what I'm doing, but I'm never wholly convinced that I've reached stats perfection, on account of my aforementioned thought experiment! :D