For instance, states like California, Oregon, Montana, and Massachusetts have "clawback" provisions, meaning they may tax deferred gains if you eventually sell the replacement property and don't reinvest within the state.

I am planning to build a business to replace my income in couple of years so as to have monthly cash flow equal to my W2 income.

If they are cash-flowing and easy on management, there is no reason to refi to pull the equity because you will really hurt your cash flow with the higher rates.The best first flips to me are dumps that only need direct replacement and not a square footage add or a ton of walls down just for timeline integrity.

A subsequent cash-out refinance of the replacement property (e.g., $250K on a $1M property with a $500K loan) is treated as a loan and generally has no tax implications related to the 1031 exchange.

and having to replace appliances. 

You can look at a mobile home and see it as an easy rental with new carpet, trim and some paint but there are other bigger uglier expenses that can come up.Roof Replacement, soft floors (water damage) in kitchens and bathrooms- most floors are particle board, exterior door replacement (special order), underbelly insulation falling, bad hot water tanks with rotten floor underneath (real joy), bad windows (water again), bad bloated siding (water), water damaged base frame around perimeter of home, cracked tubs (special orders) and frozen pipes (Good luck finding a plumber to come work on a mobile home- they do not exist). 

.- My Goal: to have $10k/months of income to replace my day job.

I personally would have to have one of the windows replaced before I'd feel comfortable renting it, but that's just me and based on personal experience including a traumatic one from childhood in watching the apartment building next to ours burn in the middle of the night.

We keep "kiddie" as we say backhome which is a pot of money set aside for rainy day fund in case we need to replace appliances, perform repairs or other capital improvements. 

I am replacing all 4 toilets.