In response to your second paragraph: it's nature to use 前面 with persons.
前面 can stand for "prior" to indicate relationship about logic or time.
When using as "prior", 面前 cannot replace 前面:
他在我前面加入这家公司,比我多干了3年。
He joined the company before me and worked 3 more years than me.
While 他在我面前加入这家公司 means "in front of my face", I saw him joined this company.
前面 mainly refers to a direction, while 面前 gives a sense of something is near when referring location(usually can be easily seen). It's strange to say something you can't see is just in front of your face, isn't it?
For direction:
A:那家超市在哪里?
B:在前面,沿这条路过5个红绿灯就到。(can't say 面前 here since the supermarket isn't very near)
A: Where is that supermarket?
B: In front of (us), follow this road and pass 5 traffic lights then you'll reach there.