I wouldn't change a thing. Get an attorney (do not take referrals from ANYONE already involved in your transaction) and have at least 2 different abatement contractors come out to give you their opinion. DO plan to pay them for their time, at least $60 an hour. You are paying for their expertise and they shouldn't give it to you for free. After you buy the house (if you get that far,) you can put the job out for bids and they can come back and bid if they want. Chances are, if you paid them the first time, you will be on a better relationship with them and get better bids and work out of them.