Hello and thanks for your post.
You have asked good questions here. I first want to mention that the application process is truly holistic, and committees will look at everything - your stats (GPA and GMAT), work experience, and extracurriculars.
Your GMAT is decent, though compared to others in your demographic, it is a bit below the average. If you haven’t already, I suggest taking it up to 3-4 times. I feel that a significant increase in your GMAT will be worth forgoing Round 1 and instead applying in Round 2. You should apply when your application is strongest. Of course if your GMAT will likely not improve, then Round 1 is better. So it depends how much higher you think you can score. You still have time though, before the Round 1 deadlines, to increase your score.
It is hard to gauge your work experience without knowing your accomplishments and impact you have made there. It is nice to see that you have taken the lead on recent projects, as well as having already been promoted. It’s important to show you have made an impact and demonstrated leadership. Ideally this will be supported by strong recommendation letters as well. It will also be important to explain why you want your MBA, and to also illustrate the skills you already have which are transferable. Be sure your story makes sense, and is realistic and specific. It is not ideal that you already have an MBA, but if you can discuss a compelling reason, then that will not completely hurt your chances. (And to answer your other question, you will also have to explain – perhaps in an optional essay – what you were doing productively during your gap year.)
Regarding extracurriculars, make sure to really emphasize your leadership roles you have taken on. Being a co-founder sounds impressive; that is one aspect of your profile on which you can elaborate.
If you continue to strengthen your profile, you do have a chance at some of these schools, but they are extremely competitive. For that reason, I suggest apply to several schools, including reach, target and safety, and your current list illustrates this, although I don’t see a true safety school on here.
Good luck!