The rules that you quoted under "Special Rules for Dependents of a Qualifying Surviving Spouse" are either poorly worded or just plain wrong. You certainly will not find that same wording in the IRS Form 1040 instructions or in IRS Pub. 501. You didn't say where TurboTax says that.
In fact, there are no "special rules for dependents of a qualifying surviving spouse." There rules for whom you can claim as a dependent. Those rules are the same whether or not you are a qualifying surviving spouse. There are also rules for a child who qualifies you to file as qualifying surviving spouse. That child might or might not be your dependent.
Just ignore what you said "TurboTax says." They tried to combine two separate sets of somewhat confusing rules into one set of rules, and they didn't quite get it right.
In Pub. 501 see "Qualifying Surviving Spouse" on page 9, and particularly eligibility rule 3 in that section. Rule 3 refers to a child "whom you can claim as a dependent or could claim as a dependent except that. . . ." So you might have to refer to the rules for dependents starting on page 11. But keep in mind that rule 3 for a qualifying relative (the "gross income test") does not apply to a child who qualifies you to file as qualifying surviving spouse. The gross income test is item "a" under "except that" in eligibility rule 3 for qualifying surviving spouse.
