It sounds to me like all your ideas are good, so just make stories out of all of them. What I mean by that is, do what manga artists in Japan do: start out with one-shot stories spanning one issue in length (usually 22-32 pages). You can make introductory or "pilot" chapters of your longer story ideas this way. Then, as you get used to doing comics, you can graduate to doing longer stories, spanning maybe 1 graphic novel in length (128 or so pages) and containing 4-6 chapters. This is more reserved for your longer story ideas.
The point is that if you really want to do comics that people will enjoy (without the hassle, hustle, and bustle of working for a comic book employer), you have to practice doing so, and practice often. Always find time to do your stories and draw your pages, no matter what else is going on in your life. Even if you have to wait until late at night, and only do it for 15 minutes to an hour, that's 15 minutes to an hour of honing your skills and gaining knowledge on your craft that you didn't have before. We can't all be Mozart, or Walt Disney, or Osamu Tezuka, or Charles M. Schulz, guys with that kind of talent are so rare that there's only a few born in a lifetime. But if you practice, you can be successful at what you do. (And I'm not talking money. That comes later, if your skilled enough, knowledgeable enough, and lucky enough.)
And there's no time like the present, take it from me. I've been in your shoes for the last 20 years, and I just now started showing my artwork to the world on this forum. Pick your craft, learn your craft, practice your craft, show off what you've got, and learn exactly what works and what doesn't from others' opinions and advice, then make something better next time that doesn't have the mistakes others have pointed out. Rinse and Repeat. Eventually you'll find your voice, your style, your niche, and your audience. And when you do, stick with them as much as possible. As others have said, just do it.