The $2.5 billion agreement announced last week that will have BB&T Corp. buying Susquehanna Bancshares Inc. is a big deal inside and outside of Baltimore. We know some details on how Winston-Salem, N.C.-based BB&T (NYSE: BBT) plans to proceed once the deal gets the approval of regulators and stockholders at Lititz, Pa.-based Susquehanna (NASDAQ: SUSQ). But we don’t know all of them. Here are four things to watch as the transaction plays out in the Baltimore market. Will there be branch closings? Banking…