... 前に => Before ... N4
Relationship before and after
[後「あと」]で => After V1, V2 N5
Time
... 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
〜がさいご(が最後) => if you do... negative result N1
Decisive (resolute decision)
手前 => considering; before; in front of; one’s standpoint N1
たが[最後「さいご」] => Once A occurs, B happens N1
Information, Report
~[前「まえ」]に => Before N/Vる(occurs/happens) N5
Time
当然だ/当たり前だ => natural; as a matter of course N2