... はずみ.... => So N2
Result
に先立って => before; prior to ~ N2
に[先立「さきだ」]って/に[先立「さきだ」]ち/に[先立「さきだ」]つ => Before A occurs/takes place N2
Time, Situation
まずは => Temporary, first of all N5
Consider it
…ば…はずだ => If ... then perhaps ... N3
Speculation
はずだ/はずがない => it must be; it should be (expectation)/cannot be (impossible) N3
…はずではなかった => cannot be (impossible) N3
Surprised
... はず => it must be; it should be (expectation) N3
Cause, reason
... たはず => it must be; it should be (expectation) N4
Speculation
はずだ => it must be; it should be (expectation) N4
に先駆けて => prior to; to be the first (pioneer); being ahead of ~ N1
~はいわずもがなだ      => need not to say N1