Pinnacle, you will have to explain the situation a little more, but you are getting partially correct answers.
The amount of rental income used is 75%. As far as wether you can use the rental income, it will depend on whether you have showed income on past tax returns, or if you expect to turn a primary residence into a rental property when you buy a new primary residence. If you are buying a new multi-family, you would use 75% of the projected rent according to the appraisal. Banks are all requiring different amount of reserves, but most of them are 6 months on the investment property plus 2 months on a primary.