... 前に => Before ... N4
Relationship before and after
~助詞+数量      => Corresponds to the verb...of quantity N5
Quantity
... 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
手前 => considering; before; in front of; one’s standpoint N1
~[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