Rules of thumb are a very lazy way to do business.You can build a generic pro forma and plug every applicable number in, take five minutes, and come up with a reliable look at your future CoC, CoC including principal repayment, IRR, etc.Build your pro forma to reflect the base case and then the pro forma case.

What is a creative way to form a relationship with an agent, where they can help you quickly figure out ARV and potential rents for a wholesaling deal?

I'm not sure where you are getting your pro-forma rents, but those look super high for a 2/1 Roy apartment.

Researching a stock involved developing complete pro-forma financial statements and valuations using primarily DCF models supported by comps.

You also will not be receiving most of your rent monthly and that 15% is also going to be at full occupancy.Like others said the pro forma you read is a sales sheet.I don’t see anywhere where you are taking out insurance, cap ex, property management cost, etc.The average price per door is $75k so if you are buying 16 doors for $500k you are looking at F class deals.

You will need to run pro formas on various planning options as what you can do and whats the best fit.

Rents are below market pro forma has rents at $100-200 more per unit.Mortgage, taxes, insurance, and other costs roughly $3000/monthSelf managed. 

Don't allow financing or a finance contingency (it can be a good indication they are selling above market value)Don't allow for your own independent property inspectionAre not realistic with their pro forma's (i.e. they don't include vacancy or maintenance projections or use unrealistically low vacancy factors)Require you to pay for any renovation upfrontSell only in cheap. low end neighborhoodsDon't accurately represent the neighborhood/property classificationDon't have consistent rehab standards for all propertiesDon't provide a scope of work for the propertyCan't provide references of repeat investorsRequire you to close before a tenant is in place

It can be difficult to try to build all of the potential costs into the pro-forma especially early in the process without a buildable plan, and to some degree it seems the cart has to go before the horse because you don't want to hire the architects to get you a "for construction" plan if you don't have your muni approvals yet. 

Will the bank look at the pro forma rent roll and size the loan from that or the typical appraisal process?