NJBizSchool:
Responding to your questions:
(1) Qualify for the test waiver at Stern for people with over 3.4 in business undergrad; would it still be wise to take GMAT?
If you think you can do exceptionally well and it won't require a huge amount of prep, then give it a go. You don't have to submit since it's not a requirement for you. It might also help with potential scholarship money if that's a consideration.
(2) How does my profile stack up for admissions to NYU Stern part-time?
A little on the younger side, but well within range.
(3) Should I disregard my previous MBA coursework on the application?
I am not sure what precise you mean by "disregard," but it's not really relevant for your application to NYU Stern.
(4) What can I do to strengthen my profile?
I don't see any extracurricular activities or outside of work leadership. That's an important part of your profile and overall application. I don't have a strong feel for your work accomplishments too, so hard to tell if there's a particular area you need to focus on there as well.
Please reach out if you'd like to discuss further and would like a free consultation:
https://admissionado.com/free-consultation/