Insurance is just an expense to factor into your underwriting just like property taxes.

Be mindful of short-term capital gains tax, as profits from flips held for less than a year are taxed as ordinary income, and frequent flipping may result in self-employment taxes.While profits from flips do not qualify for 1031 exchanges (since flips are considered inventory, not investment properties), you can minimize your tax burden by deducting allowable expenses like renovation costs, loan interest, and holding expenses.If you're considering diversifying into rentals, explore opportunities to benefit from long-term tax advantages such as depreciation and lower long-term capital gains rates.

Before the income subject to UBIT is calculated you can depreciate and deduct expenses and losses on that portion of the income so generally it's not as bad as people think. 

In MA, you can usually get insured with Fair Plan with certain pets, but it is VERY expensive.  

Again at the expense of PAYING 30 years of principal in a shortened time period.

See if you can negotiate some selling or moving expenses with the company hiring you. 

One thing I can assure you, there isn't an asset class in the world that would have me comfortable at 100% leverage.Your money on the sidelines is great in principal but in reality it will be put to work covering the net loss on the properties you buy as you will be overleveraged and won't be able to cover your operating expenses with the rent.

Would it be more expensive to buy an older property like this vs buying a new construction in TX? 

Most home owners are only familiar with California Closets pricing and automatically perceive closet fit outs as being expensive.

Cash-flow is for "keeping the lights on" as in covering operational expenses to defend against any need for additional capital investment.