Even better, the item you didn't put on your list grows your income faster than many of the options you have listed. 

Only homes that are offensively overpriced are sitting any length of time.And yet there are still distressed sellers whose homes are in no condition to list, or who need a solution faster than a real estate agent and a buyer who needs a loan can work.

Just pay it down faster if that is what you are wanting to do.  

Your credit union may be able to do one of these lines faster than the full construction mortgage that you have already tried. 

However, the advantages of having Multifamily properties are it scales faster and an opportunity to get higher monthly cash flow.

Its a similar model to a gym membership, they provide some resources, but you are charged whether you utilize the weights & treadmill or not.A lot of brokers, such as myself, don't charge "junk" monthly fees to their agents. 

I can advertise for regular tenants, but they can help the business succeed faster if they are interested in being the first tenants.What do you guys think?.

That way you can scale faster.

This will help you analyze your next opportunities faster and with less misses.

Interim money at say 6 to 8 percent plus points, that could be done faster and with a bit more leniency would be very attractive.