Traditionally, banks rely on the analysis of customer financial information from payment flows and accounting records.

(Monthly statements containing Financial items/M&R costs/GC Costs).

If a cash buyer wanted to put his property under with me (property newly renovated), could I flip it to a buyer with a traditional bank loan, or will the bank reject a whole sale contract?

They simply have slightly higher rates than what you would find traditionally.

It is not an earth shattering concept but often the foundational items are what make a good/bad decision or deal. 

I don't have a traditional income (just started a digital company with international clients, and most of my equity is based on stocks), so I don't qualify for regular loans.

Also will have large ticket items or Capital Expenditures you will need to set money aside for to make repairs when the come due like the roof, siding, HVAC, and etc..Lastly the turn over process starts it all over again minus the loan and closing cost aspect.

If you have no money right now, I would recommend traditionally purchasing it from your Mom, put a small mortgage on it and get some cash back from the mortgage to keep on hand for reserves.Good luck on your journey and do not let this opportunity pass!

Beyond that, there are a couple of big ticket items like the roof which may need replaced, and the wiring because I'm not sure if it's got aluminum wiring or not. 

Property management is a separate cost, and 10% is usually what I account for that.It has worked for me for properties that don’t need a roof or foundation (ie high capex items) at time of purchase.