re: 5yr. Balloon Loan w/ 10yr. Amort. (Any hidden things I should worry about?)

I don't think a balloon note is a "safe" move at all.

However, you have a clear plan and do not appear to have the dreaded disease of "our income will never be enough to retire this debt." Having a clear plan and solid budget fundamentals is literally 90% of the battle - take everything else I say with that in mind - you're "probably" fine with your plan.

On the other hand, what you're going to struggle with is the rising internal expectations associated with your rising gross household income. I'm of the opinion that you should live like monks - now - get the debt at least to an easily manageable level, and get off the train of paying a lot of interest with little retirement of the principal.

That balloon note will be sitting out there waiting - like you will have paid all this money and still have to make that loan and pay it all over again. That seems (potentially) demoralizing and self-defeating.

You didn't talk specifics about current income or expectations and I respect that. However, I would go back to square 1 - cut spending to the absolute, painful bone, until you cut the overall debt load (possibly excluding the mortgage on the primary home) to half or less of what it is now. Otherwise, in your shoes, I would feel like a debt slave for the foreseeable future.