If you are planning to buy some new home and no inventory there. I guess you need wait for a long time for closing. For me, my closing day is around this Dec. So no bank can hold the rate so long, except for TD, since the minto has some deal with TD, I guess.
So the rate must be up within this year. so your current locked rate will be very cheap at the closing day, if your case is similar to mine.
that you can cancel the contract. i believe you can cancel the contract within 10 days. based on you said, you might not be able to do that but you might be able to do sth. if you consult with your lawyer.
because you had the chance of looking and inspect that house. i believe you can do sth by the time you placed the offer but you might still get in a situation of lawsuit. Not the time when the title has been transferred to you. It would be just easy to sale it afterwards if you do not like it. Nowadays, if you can do DIY, you might be able to make money
see this kind of question you can not have a smiple answer you need talk to your lawyer.