I think that changes around that time when you run out of conventional loans and have to start using commercial lending.

Is it smart to partner up with someone else, whether its seller financing or otherwise, to provide capital for the property with someone who does not have a portfolio yet?

As a current Mortgage Loan Officer, I'll tell you this: you're not crazy. 

Loans are based off your net income if you are a sole proprietor like myself, so the more expenses I have, the less eligible income I will have for loan calculations.Does anyone know how small to large size companies get loans?

Many lenders, including ourselves, will take your past projects into account when offering you better loan terms.If you have a proven track record, we can help you secure even more favorable terms on your next flip.

Bridge loans are extremely RISKY. 

Sorry.We also won’t make a loan on a tenant-occupied flip.

Just won a bid at auction.com and my lender provided me with a preapproval but they rejected it saying that it cannot have any condition on it, is it possible por my hard money lender to give me one with no condition?

Your goal is to obtain a "loan", How?

So I did a few deals where the partner brought the cash and I used my credit to get the loans, and we split everything 50/50.