That being said, you can use a primary home loan with rental income to subsidize it. 

It's reassuring to know that having parents as co-signers can help keep them financially accountable.

I strongly suspect your best move is to roll the TSP to a Traditional IRA and convert the IRA to a Roth, using non-retirement dollars to pay the income tax, even if you have to borrow the tax liability. 

I'll check with my accountant to be sure.  

If you’re going conventional on a second home, you might want to consider putting even more down and make sure that your debt to income ratio is <41%, and credit at or above 780, ideally, as the GSE’s just made changes to the Loan Level Pricing Adjustment (LLPA) just got even more expensive effective 05.01.2023 but most lenders will either incorporate this into their pricing or will then. 

Quote from @Candi Kham: SOFTWAREGood software will handle management, accounting, and application screening.Software is a common question on BiggerPockets.

I'd like to continue house hacking, but because I'm a real estate agent on 1099, I need a solid plan to generate more income to help with qualification.

ADUs and their income potential are a hot trend right now in real estate investing and as usual, the conventional lenders (FHA etc) are going to be slower to adapt

You have an unrecorded operating agreement giving you 99.9% of the income, assets, losses,etc.However, this is probably overkill.   

@Logan M. it’s because agents are owners receiving stock awards and passive income opportunities for life just for supporting agents who join the company.