@Bradley Buxton makes a very good point to make sure to do your due diligence as you won't be an owner occupant like your in-laws.Last bit of advice: Because this is a friendly deal, you want to take your time to make sure you structure it in a way that maximizes tax and cashflow benefits for both parties. 

Anything involving a service animal and ADA should be directly consulting an attorney on the matter as every case is different. 

Focus on tax-saving strategies such as cost segregation studies and bonus depreciation to accelerate deductions.By qualifying as a Real Estate Professional (spending 750+ hours annually and materially participating), you can offset your wife’s S-Corp income with real estate losses, reducing your tax liability.

If you do not get that tax credit its usually not profitable. 

The land is on two tax lots so my plan is to sell the extra lot immediately after closing for a projected $275K.The property on the other lot will be a fix and flip with projected costs of $240K and an ARV of $750K.I plan to use a PML of 2 points and 12% APY for 70% of the total cost.

If you're going to do it alone, make sure you your due diligence: estoppels, inspection, review, consult with a local attorney familiar with the local regulations, etc. and good luck.

I highly recommend you study this, practice it, and apply it.https://www.biggerpockets.com/blog/rental-property-cash-flow...Property Details:Type: Single-family homePurchase Price: $289,900Down Payment: 20% ($57,980)Loan Amount: $231,920Interest Rate: 6.85%Loan Term: 30 yearsMonthly Mortgage Payment:Using a mortgage calculator, your principal and interest will cost $1,515 per monthRental Income:Average Rent for Single-Family Home: $2,171 per monthOperating Expenses:Property Taxes: $300 per monthInsurance: $100 per monthMaintenance and Repairs: Budgeting 5% of rental income ($109 per month)Vacancy Rate: Assuming 5% vacancy ($109 per month)Property Management Fees: If outsourced, typically 10% of rental income ($217 per month)Total Monthly Expenses:Operating Expenses: $835Mortgage Payment: $1,515Total Expenses: $2,350Net Monthly Cash Flow:Rental Income: $2,171Total Expenses: $2,350Net Cash Flow: -$179 per monthConclusion:In this scenario, the rental income of $2,171 per month does not fully cover the total monthly expenses of $2,350, resulting in a negative cash flow of $179.

Taxes and insurance will be another $400+.

Are you quoting net cash flow - after taxes, insurance, maintenance/repairs, property management if needed? 

but keep in mind CA has higher taxes and reg fees and I’m not doing more than 1-2 flips (short timeframe flips)  a year and many years do 0 flipsDo most flippers put flips into LLC Or in personal name (sole proprietor)  in CA (where you must pay $800 yearly plus accounting and other fees $300to $600+ yearly to maintain LLC) Pros for personal name-save on taxes accounting.