Why would #3 and #4 be suicide? Maybe for PM May, but doubtful the Remain MPs and those who "found out how bad Leave was" would actually claim a political boost?
On the Conservative side - many of the remain MPs come from leave constituencies. Also, as a party, the Conservatives have a strong leave bias. If the leave does not happen, it is hard to see the Tories making it back to power for a considerable time.