Each situation is unique. But this is similar to the situation that I was in a few years ago - I made the decision to rent it, and it was the best financial decision of my life as it got me started in my real estate investing.
A few thoughts:
I would try and not focus on 'how much cashflow will I make/lose each month' and instead ask 'how much cashflow will I make/lose over the next 5 years.' You're smart to be thinking about things like vacancy and rehab as those will always lead to bad months. However, if you have those bad months, and still be making money long-term, you may be OK.
According to standard metrics, it sounds like your house would be a below average investment. This is a complicated discussion, but generally speaking, I'd want my rent to be twice my mortgage (including PITI).
But even a below average real estate investment may be a good decision if it's better than the alternative, and gets you started. Your first investment will be your most difficult investment to make, and it's hard to think of an easier to get started than using your old primary as a rentals.
Real estate investing is great, but buying and selling real estate is very expensive. And while the down payment is simply your cash that becomes your equity, there are other huge expenses that convert your cash into nothing at all. Conservatively, it will cost you 10% of the gross cost of the house to sell, and around 5% to buy. So, if you wanted to sell your 100K house and buy another 100K house that's a better investment - that will probably cost you around $15K in expenses (i.e. money that you burned).
So, reading between the lines, I'd say that keeping your house may be a good decision, if it's not the best investment.
This is all contingent upon one thing, and you already know what it is: your ability to manage the risk. I'll sidestep the insurance/LLC discussion for now, and say that you both cash, and excess cash flow to keep this as an investment. How much cash? At least $10,000. I'd actually recommend something like $20,000 + your personal emergency fund. Then, you also need to be able to have a positive cashflow, by a fair amount each month, factoring in your rental being vacant. If you couldn't absorb the additional PITI with your current income, I'd be hesitant to go this route.
So, the decision is yours. And it's a huge decision. For me, the decision got me started down my RE investing journey.
Happy hunting.