|Perl Monk, Perl Meditation|
The examples that you have given are now considered acceptable spoken English, but not formal English (although that is fast approaching).
They could be written more formally as:
Who does Kim think the coworkers want management to replace her with?and
Who does Kim think Carol hopes Jim says the coworkers want management to replace her with?
The grammar in the formal versions is more closely related to Latin grammar, but it introduces a stiffness into the construction that appears to be a dying trend. Forms that, 20 years ago, would have been considered errors, are now accepted practice and come more easily to the tongue, such as:
Ending a sentence with a preposition: Who ... with as opposed to With whomand
The split infinitive:
...and I am pleased that it is so. I love the flexibility of English, the fact that it is so adaptable, but it does make parsing it hell!
update jporter correctly pointed out that this is not a split infinitive