I've been working with an amazing agent, after interviewing a few, and am looking for my first house hack (most likely a 3 fam North of Boston in like Everett, Revere, Malden, Chelsea).

Is it unrealistic to interview some realtors and be honest with them that it may not happen for awhile?

It emphasizes the need for confidentiality and specifies the penalties for a breach.Depending on the nature of the business listed, I will call the prospective buyer for a brief interview to see if there's enough of a fit that an NDA is even warranted.There are plenty of cases where I get queries from dreamers who are completely unqualified to buy the business, whether it's a lack of experience or a lack of funds. 

And even ones that interview great and look great on paper turn out to not be great.

I would love to hear what types of questions you ask when interviewing a commercial GC.

Once you have interviewed your buyers you will have a very clear set of criteria from a group of people that are actively buying.

If you are doing HR and interviewing prospective hirees, unless another HR person is sitting there next to you all day, you will have no idea if you are basically talking like a 'blithering idiot.'

I'd come up with a list of 3-4 options and take a list of questions with you to the interviews. 

Regardless of how you find them, try to interview at least three managers1.

Which means always interview at least 3.