I'm also currently negotiating several 5-10 year leases on a mixed use property of mine and the thought crossed my mind that I don't have a contingency for a high inflation scenario - my annual rent and CAM increases are 2% and 5% respectively. 

I want to explore options of how to leverage the duplex to get home equity lines of credit or similar revolving lines of credit.

Just pass it through to them in CAM expenses.

It's a revolving line of credit I can use to pay any business via ACH payment.

I listen to anywhere from 1-4 books a week mostly revolving around real estate, investing, and building businesses.

If I'm low on capital do you think it would be better to get an unsecured revolving business line of credit (not a credit card) backed up with a personal garrenttee between $50k to 100k to use as a down payment (with a llc) conventional 20%/25%/35% (I honestly don't know how much percent the downpayment would be one of the three) on a small commercial  investment property 5 to 50 units instead of getting the four plex with a fha and househacking it and only having to put 3.5% down.

If I'm low on capital do you think it would be better to get an unsecured revolving business line of credit (not a credit card) backed up with a personal garrenttee between $50k to 100k to use as a down payment (with a llc) conventional 20%/25%/35% (I honestly don't know how much percent the downpayment would be one of the three) on a small commercial investment property 5 to 50 units instead of getting A fourplex with a fha and househacking it and only having to put 3.5% down.

Refi as you mentioned and keep your line of credit revolving into the next deal.

Once leveraged fully, since I usually do 2-3 year variable rate mortgages with automatically readvancing revolving (heloc) portions I simply renew the mortgage to the full balance.

@Jeremy Lee the core of the flipper interest is going to revolve around price.Fun notes and exceptions: If you only have stated value coverage, and not replacement cost coverage, this could very easily blow up in your face, particularly if you owe a lot of money on the property.