Most likely you will need to get everything approved by the HOA.

Is your pursuit of what you want more important to you than the approval of your parents? 

Yes I have been pre approved already.

We chatted for almost an hour, he showed me around his place, and I got to know a bit about him—a really nice guy.Then, at another spot, I drove up just to look from the outside (since it was “showings for pre-approved buyers only”), but the seller came out, curious about what I was doing.

I finally got word of an approved application. 

What kinda hurdles do you have to overcome to get approval, and how long is that process?

One hurdle you may have depending on location is zoning approval.

Some of the laws in NY changed recently and you are required to obtain a certificate of no harassment, No permits will be issued until it is resolved.You will need to work with the current tenants for this certificate to be approved which can take up to a year or more, Definitely something big to consider.  

Quote from @Raghavendra Jakkani: Yes, you should screen and approve every adult living in the home, whether they contribute to paying rent or not.

You may spend thousands of non-refundable dollars to present them with deals, but there is no guarantee of approval.