In truth, my goal has always been to replace my W2 income, so the focus was on the $ coming in every month, and not so much the number of properties.  

So, the landlord makes an extra $1000 per month with the same fixed costs.  

Only tankless water heaters, extra insulation, heating/cooling, etc....

That is assuming your DTI can cover the increased mortgage payment.If you have use for that extra $100k that you would get back right now then don’t wait.

Maybe they want bigger lot, more land, extra lots. 

maybe just me, dont go cheap on TP. you can buy inexpensive, but make sure it doesnt feel cheap. its worth an extra couple of dollars so guests dont remember that everything felt cheap

That’s just the truth but all isn’t lost:- Created actionable steps, Created a system that can actually produce the desired outcome.

Typically how  much extra should I budget for, for these unknowns? 

While I am extra nervous I am trying to make this an investing opportunity and decided to house hack or buy a place to rehab which I can later rent - let’s see how the DC market treats me.Suerte a todos y un placer ! 

Just keep in mind that condos still have HOA rules and fees, which can sometimes limit rental options or add extra costs.