who. that

Consider this sentence from the New York Times — specifically, the text that comes after the colon (I added the emphasis):

“The fact that the bill could slightly add to the federal deficit did not dissuade House Democrats from voting for it, in part because the analysis boiled down to a dispute over a single line item: how much the I.R.S. would collect by cracking down on people and companies that dodge large tax bills.”

Now, if I use the word “people” (or refer to a person), then grammar demands that the word “who” follow. By contrast, inanimate objects (basically, everything else, including companies) get “that” or “which.”

But what happens, as in the above example, when a sentence contains both “people” and “companies”? Does “people” always predominate? Or is the last pronoun (in this case, “companies”) the deciding factor?

In other words: Is it “companies and people who” or “companies and people that”?

My understanding is that the inflected word that must apply to each element is governed by the element listed last. Thus:

“companies and people who”

or

“people and companies that”

A colleague disagrees. He says that we must stick to whichever pronoun works for both antecedents. Thus:

“companies and people that”

or

“people and companies that”

But not:

“companies and people who”

or

“people and companies who”

As for who’s right, I’m sorry to say that Bryan Garner, the leading voice on parsing precise usage, has not responded.