This is incredibly common. 

This approach takes commonly available materials, just installed or constructed differently, to create a solution usable to all or as many people possible.

That being said, sale rates have fallen and price reductions are now more common on listings, I previously noted City plans in the area that could impact growth, and it's anyone's guess what happens to markets over the next year.    

I'd say about 4K would be more common.

At the lower price points, refrigerators are very common as you move up lesser so but still pretty common.

If all of you will be on the mortgage, then you could treat the investment as tenants-in-common, which means that you each own a specific fraction of the property and you split the revenue and expenses proportionately. 

Not implementing increases is one of the most common mistakes among new landlords.

@Darrel Hernandez This can be a common strategy to pull the equity out of the property through a HELOC versus a refinance.

But the common narration that "I'll just do a few flips/wholesales and boom I'll have enough money for a down payment for that xx unit building" is so much more complicated than advertised. 

While they can be developed in some areas, don't assume this strategy is common place and make sure to do some solid due diligence before purchasing.