With one small exception on VA loans, there is no getting around the due on sale clause. 

Also, with a VA assumable, if the one assuming the loan is not a veteran, then the seller (veteran) entitlement will still be tied up in that property.

Most people don't qualify for that relationship.The seller financing will not show up or affect the credit score.However, when applying for a loan at the bank or especially a Federally Guaranteed loan, they ask on the application for ALL Loans, whether  or not it shows on a credit report.

I’ve been wanting to speak with someone about that but I’m not sure who would be the right person to ask ( real estate agent , broker etc) . 

If you're purchasing a single family home you can use traditional financing like you probably did on your house or you can do a commercial loan.

Most agency loans will expressly forbid such an arrangement, so if they found out, the odds of having the loan called would be very high. 

That will be the best spot to meet an investor friendly agent in person or at least meet other investors in your markets that can help connect you to the right agents.

The GC is a business person who doesn't care about your ARV, LTV, or your budget.

Quote from @Matthew Crivelli: Personally, I'm not a fan of Air B & B.

But the risk to the seller on this deal is immense you have a guy tying up a property who has no ability to close it and then sell it to whoever will give him money and that person could be nefarious get into title rip rents could give 2 craps about the sellers credit etc etc..