By having a higher credit score or lowering your LTV you can reduce your interest rate and help to increase your DSCR.3.

In my experience, the local banks are going to get you better rates and lower fees with their commercial loan products than the "DSCR lenders".

Regarding price, do you have any suggestions on how I can get him to agree to a lower price?

I recommend using a lender that non-reporting to personal credit and can close under the LLC to keep your DTI lower and overall your personal liability profile more bankable.

My guess solely looking at your numbers is that it's an older/distressed property which means you have to account for more costs in capex. 2nd thought being it's not in the best of neighborhood then you'd have to take into consideration lower quality tenants/ neighbors and maybe increase expected vacancy and late payments.

Suggesting to them buying their house for a wholesale range offer or lower dependent on the extent of the rehab, then having a contract in place that gives them a percentage of the profit to help get them back on their feet, paying off debts etc.

(I know, nothing is certain but just hypothetically) and all cash out loans are not created equal. if you have a lot of equity you can borrow up to 60% with the lowest rate possible, which would be close to a half point lower then borrowing up to 75% loan to value. 

This lowered my cost basis per lot by 7k.

You would arguably be better off buying a CD at a slightly lower yield with almost no risk, time, or stress requirements. 

This would allow you to access some cash for other purposes ( Tax Free) because a refinance is not a taxable event.