I can't give you literal translations as they're not only useless most of the time but also counterproductive. But I can tell you this:

1. обычно люди снимают квартиру на много жителей

That'd mean: Usually people rent an apartment for many residents.

2. По-разному бывает

бывать is difficult to translate in English. Usually it is used to convey the meaning that something can happen and is very well real or in what way something came into existence. Like a child asking their mother if magic exists. - Мама, а магия бывает?

All in all the phrase just means this:

Things happen differently (for different people)

3. У всех is just a part of a very common construction - "Everyone has" in this case.

E.g. I have a sister - У меня есть сестра. Есть is the present tense of to be and is often omitted in this construction.

She has a toy - У неё есть игрушка and so on.

So у всех разные жизненные ситуации... - Everyone has a different situation in life...

кто как - is an incomplete phrase it has relation to выкручивается

Кто как выкручивается. Кто is an impersonal subject that essentially means anyone, everyone in this case in English. Как here means in what way. We talked about выкручивается already:

Everyone finds their own way out is what that Russian phrase means.

Note: it's not surprising that you couldn't find the subject for выкручивается. It looks like the person who wrote that sentence got confused with it and "forgot" to properly conjugate the verb. It should have been ... и кому как удаётся выкручиваться

Everyone manages to find their own way out.