It is very clear, that you can withdraw from this transaction, if you are less then 60 days after acceptance. Just send a letter with sertifyed mail, if you cannot contact your realtor. If you realtor do not show what you like to see , change the agent.
Cash is a king, with cash, if price is aproved by the bank, I would try to give lower offer. There is never sure bet. If someone comes and proposed more, bank can consider all offers, but again, cash is a KING.
All you need is a good agent in your area.
+3 situation it is not normal, but if you agreed upon it is in contract. The oonly you can do it is go to sherifs office or contact RE attorney, if they do not leave. Good luck
You need finished you short sale before filing chapter 7. At the minute you file all previos agreements will be void.