It’s a legitimate question isn’t it ?  

They can and do operate legitimately.

You can save a lot of money by doing the work yourself compared to hiring a contractor but at the same point you want to make sure it is legitimate.

BP IME is not a great resource for legitimate information from commercial operators - for that, just look in the tax records and cold call the owners of the type of property that you want to buy and ask them questions, tell them you're just getting started - 2 out of 3 will be happy to talk to you and lend you a hand. 

Aside from the very legitimate legal complications to work out.

There is not enough info here to know if you have a legitimate out of the contract.

For HMLs in particular, and especially if they've reached out to me, I'm looking for positive reviews and referrals showing that they are legitimate.

Is this a legitimized write off?

Join the club - I'd guess 90% of the investors I insure don't follow some or all of the above processes above and it's a legitimate exposure to you the property owner that is not inexpensively insured on your end of things.

The letter otherwise looks legitimate, other than the fact that it is at least 5 months expired.