That question depends on a lot of different factors.

This is important for the possibility of your loan getting approved but also a major factor in a seller's decision to accept an FHA financed offer over an investor who is paying cash or financing with a conventional or commercial loan.I would suggest taking a different approach with your FHA loan and looking for a property that you would want to live in for an extended period of time but also would cash flow if leased it after satisfying your FHA owner-occupancy time requirements. 

If you are feeling compelled to buy because the cash flow sounds great, be aware that a 100-yr-old house is going to need steady ongoing maintenance, which you don't seem to have factored in.

What is a developer's typical profit margin?

Hello @Sheldon Peart  If you need financing to purchase a residential property with 5 doors, you will need to get a commercial mortgage. 4 key factors affect the value of your home: Location of your homeSize, age, and condition of your property, including any renovations or updatesThe housing marketThe economy and interest ratesHere are 2 ways to help you estimate the value of your home:Talk to real estate agents – They may estimate its value for free and should be able to tell you what other homes in your area have sold for.Pay an appraiser 

What factors are considered? 

You should factor in the loss of use when you are doing the 10k worth of remodeling to the other unit. 

Also there is the factors that I would have to pay PMI on any loans with less than 20% equity...I would like some advice on this if I could get some feedback from people with experience in doing this.

In these markets people have to adjust, and this typically means investing for capital appreciation, development, or syndication; which are all great methods but a bit more advanced.

This is a major factor that has a can overshadow the typical Spring/Summer rhetoric.Do you invest in student housing?