Do the same with the hot water tank.4th look at all the cosmetic, painting, flooring, carpet,5th look at all the outlets see if they need to be grounded, see if they are two prong or three prong.

If the outlets weren't in Vacaville I promise you nobody would know where it was.

For that, what I was going to do was built that wall as a 2x6" wall, fill the cavity with mineral wool insulation, apply a flexible vinyl mass layer over the studs, sealed at all penetrations (like outlets boxes, light switches, etc) then hang the wall 5/8" drywall with resilient channel.  

., calculating the number of electrical outlets by the length of a wall, etc.).

Plans and things change unexpectedly.

This skill will serve you well whether you follow the rest of Dave's advice or not.Be sure that you have the cash reserves necessary to protect you from the unexpected.

@Julie MarquezYes, I agree there will be unexpected expenses, things that are out of your control..

I likely wouldn't do what I'm doing if I wasn't able to get on a plane any minute and go straighten things out over there as needed. and I keep plenty of cash on hand to deal with the unexpected eviction, sewer backup, and blown furnace that I know I'll have to deal with some day.

Rehabs can have unexpected issues! 

Lots of cockroaches, broken outlets, etc.