Do I read correctly that you do not have the closing funds needed to purchase your 2nd rental conventionally?
You say you have all your ducks in a row but the money is the first duck if you ask me :-)
Where are you living now, you say you have one rental without enough equity in it to refi - are you pretty confident about the appraised value of that one?
I would definitely say stay away from the hard money for now, you do NOT want to get stuck in a long term relationship there on a single property. That would be for purchase, rehab, quick sale of a property that you KNOW you can turn over quickly at a high profit, making the extremely high interest rate acceptable.
In short, if you have one rental that's doing well for you, I'd leverage that experience and repeat with today's wonderfully low FIXED rate conventional loans - depending on your current living situation, if you purchase another single fam and move into it, you can qualify for low $ down owner occupied conventional loans. You can move on later and keep that loan, but you would need to actually move into the property to start with. My local banks have told me they don't have a problem with that plan, but be sure you're updating your insurance company on the owner occupied / non owner occupied status or they will have issues with it.