School choice is one of the hardest parts of the application process. You have to do some research to know which schools are a good fit for you, especially a good fit for your research interests. See the faculty of each school, see what papers the professors of each school are publishing, for example. Who are the researchers that can really help you with your interests, and where they are?
Applying to only 7 schools seems a very small number, especially taking into consideration that you are not sure about your school choices. Every time I see a list of schools like "Harvard, MIT, Stanford" I have the feeling that the applicant is trying to go for the famous schools, not the schools that are best for them. On the other hand, applying to all top 50 is overkill, and certainly a lot of them will not be a good fit for you.
I don't think the IR score will make a big difference. Your GMAT score is great, you have a Ms, you have research experience with one published paper. If you also have strong letters of recommendation, then your profile looks really strong, a lower IR score wouldn't be enough to raise significant concerns in my opinion.
There is a lot of Marketing in your profile, I hope you have a good explanation to apply to OB. I changed from Finance to Marketing, and often people ask me about that.
If you only want to teach in a US school, I think doing a PhD in the US will make your life easier. But INSEAD is a very strong school, according to their website they have been placing students in US schools too.
I don't see why wait for another year to apply again. I think it's better to apply to all schools that you would like to go, and see the results. If you get accepted by your top schools, you accept the offer from one of them. If you don't get accepted by your top schools, you still have an opportunity with the other schools on your list.