が必要 => need; necessary N4
必要がある => Need/Need to N4
... 前に => Before ... N4
Relationship before and after
[必要「ひつよう」]はない => It is not necessary for A to be done N2
Needs, Requirements
... 前に => ... in front of, before N4
Relationship before and after
前に => before; in front of ~ N5
を前提に => On the premise of N1
Premise
~[前「まえ」]に => Before N/Vる(occurs/happens) N5
Time
事と次第によって => Depending on the progress of the situation N2
How to say the beginning
[要「よう」]するに => A. In short/put simply, B N2
Adjectival, Descriptions
要するに => in short; in a word; to sum up; to put it simply ~ N2
手前 => considering; before; in front of; one’s standpoint N1