I’d at least raise the rents that $100 to market or 25%, whichever is more.

My ultimate goal is to invest in multi-family properties, but I've encountered difficulties in raising capital.

Hey Justin,  are you using 150K in funds to acquire the property or for the rehab?   

I'm not exactly excited for my funds to be tied up for a year while the house is being built but I could borrow against myself (TSP - government employee) or sell some stock/use some of my cash ~$130k.

First, if you qualify for a Roth and are okay with volitility and no guarantees, take it, just watch out for mutual fund or management fees as that 1-2% you pay annually gets you nothing.

My asset class is very different since it is a debt fund.

If you can buy it in a LLC and the LLC is funded, then yes buy it in a LLC.I am not an attorney, but have done a lot of the stupid stuff people tell you that you should do and at the end of the day every accountant and attorney after the fact told me all of that is such overkill and just a waste of $. 

I was born and raised here, and have an elderly father who lives nearby, so I know I don't want to leave.

also, I am exploring different funding options including HELOC, HEL, etc.Given current rates are quite high and sticky, how do you recommend to utilize these funding options?

You could always invest in funds like https://fundrise.com/ (allows you to invest in RE without being accredited) or https://percent.com/ (allows you to be a private money lender without all of the work) if you have money and less time.