However, the bank indicated they cannot finance the 6-unit property and I would need a commercial loan for it.

It's ideal that you own the property outright because the holding costs on a hard money loan a lot of time is what kills development deals. 

Using the fix and rent loans and 100 percent renovations how much does such a loan costs?

Buying under an LLC shifts the type of loans you would be eligible for, and likely rules you out of considering a house hack or using an FHA/VA loan, but opens up different funding options if you have the capital for a larger down payment.

It's the same work to do a $50K loan as a $500K loan so the fees will be higher due to the loan amount but will still be much lower than what a lender or broker gets paid on a higher loan amount.

Another option is to take out a bridge loan for the rehab, then refi and take out a smaller amount of the $750,000.

From my experience, due diligence is part of the difference between the two and the interest structure (Dutch Loans vs.

how to know if it is a good thing paying cash  instead of contracting a loan?

Seeing how little of principal is paid off in the beginning of the loan cycle, my urge so far has been to throw what I have as extra payments chipping away at that mountain, but I’ve been also thinking lately if that’s a wise practice.

What type of loans or lenders should I target to get this deal locked in?