I'm changing out all of my outlets but have to use a special connector for the aluminum wiring.  

We passed up a house that all the walls were crumbling, dirt basement,  outlets in floors, old fuses, etc..To top it off, it had just snowed and I about got stuck trying to find the drive which sloped down.

You may get excited, but make sure that you have some reserves for those unexpected situations that inevitably crop up.

Once we get our finances under control (had to put a whole new heating system last fall, frozen pipes, and lead removal has set us back about $35K in the last year so always plan for the unexpected!!)

The neighbor allowed them to connect to his outlet for two days, but as of this morning they are without water until the well pipes are replaced.

Nothing unexpected in that statement.  

You really have to adapt to taking advantage of tiny bits of work time--but it's hard to readjust when the baby wakes up unexpectedly or just won't cooperate.

Your money is made at the time of purchase and based on the scope of work as outlined in your post, at a $80,000 purchase price you won't have a good enough flip margin with a contingency budget for those unexpected "profit killers".

I'm pretty risk averse so I like to have room for the unexpected.

Had I used your Rule of 5, I would have bought both of them and had multiple tens of thousands in unexpected expenses.