It's essential to check with the administrator of your husband's 401(k) plan to confirm eligibility criteria.Plan Rules: Each 401(k) plan has its own rules and regulations governing loan eligibility, loan amounts, repayment terms, and other aspects of borrowing from the account.

Our current focus is working on 1-4 unit fix and flips, but eventually work towards being able to refinance properties and keep and cash flow them.My question is  tailored on the the way I should structure our relationship for the legal and tax base purposes.Should I secure the deals under my business and pay my partner out of my business operating account?

You can find good deals on the foreclosure list or tax list. 

Also there are weather issues with Indiana winters and pipes possibly freezing, thunderstorms and hail damage2) Knowing how long to hold onto a property, 1031 exchange it to another property or DST, or in some cases sell it and pay the small capital gains tax (if any) to have less headache. 3) Underwriting the deal incorrectly (factors: local appreciation, rate of rental increase, economic growth, gentrification of area) and being overly optimistic (a renovated 100 year old home is still going to have problems).

DSCR loans deal with the amount of rents the property will throw off minus insurance and tax liability. 

I'm going to have to crunch a lot of numbers for the loan, property tax, maintenance (which should hopefully be low on new builds), and I have to figure out how to obtain an insurance policy for the units. 

Same goes for number of LLCs and what to fund them with, since bear in mind that CA tends to be more cumbersome and expensive to have LLCs than other states.California is generally more cumbersome than other states when it comes to taxes and filings.

The house is a 3b/2ba 1,895 sq ft home but an additional sunroom built in which brings sq ft up to 2,055 (based off tax records my agent found).

I'm currently living down here but all my financials (assets, bank accounts, income, tax filings, etc) are in the US.

We were even able to save the borrower from paying the hefty NYS and NYC recording tax by arranging for a CEMA with the existing note.