You sound like a very switched on individual with your head well and truly screwed on your shoulders. 

While extra coverage sounds nice, it ended up being a lot more expensive. 

What should I say to buyers without sounding annoying?

All:I am active duty military - been in for 6 years. My goal is to do a full 20, get out at 42 years old, and be done working with enough money to cover expenses + have ~$10K/month excess. I currently own a 4plex that...

Welcome to BP and it sounds like you got some great goals.

I easily qualify for the loan, have the funds available for the down payment, and an 840 credit score and am wondering what the catch is because it sounds too good to be true. 

So this one may sound silly but could keep you from committing to an agent that won't feel comfortable doing what you need done. 

It doesn't sound to me like you're going to have quite enough equity in that condo to get the 30k that you're wanting. 

That variance in debt service payment can make or break the cash flow number. 12% sounds ridiculous, but if the deal will support it, it is simply another expense like a roof or kitchen cabinets.

That situation is MUCH MORE WORK so only a tiny slice for yourself sounds reasonable.