Usage of the structure "кто ..., у того ..."

Question

А кто пачкается за столом, у того и душа запятнана.

I just heard this, and given the context, I assume that the combination of "кто ..., у того ..." means "those who ...". I wonder if this is a variant of "Тот, кто X, Y" and "у того" is added to the second clause since the idea expressed by "душа" requires "у + кого-либо"?

Is it possible to paraphrase this sentence without using "у того"? Or do you need to use the word "тот" accordingly, whatever its declension, in combination with "кто"? For instance, can I say something like this?

Кто ведет себя как избалованный ребенок, с тем хоть в чем-нибудь соглашаться нельзя.

Answer 1

This is a spoken version of a construction

А у того, кто пачкается за столом, и душа запятнана.

This more literary form doesn't come very easy in the flow of conversation being somewhat counterintuitive, since the main clause gets interjected with the subordinate one.

Indeed this is the same тот, кто... in oblique case and у + Genitive is definitely required since it implies possessing of the soul. In Russian possession of inherent inalienable personal qualities is expressed through у + (pro)noun in Genitive, e.g.

She has green eyes = Her eyes are green - У неё зелёные глаза

You can't dispense with тот in the relevant grammatical case unless you just replace it with a noun у человека for example or у людей, however these nouns entail replacement of кто with который/ые

Your own sentence syntactically is perfectly correct for the spoken language. The only thing is that хоть в чём-нибудь doesn't sound idiomatic and needs to be replaced with ни в чём. So in a more literary rendering it should be

С тем, кто ведет себя как избалованный ребенок, ни в чём соглашаться нельзя