Quibble about my word choice all you'd like, but use a direct IQ test at your own peril.
Insofar as its true that such a peril exists, the same peril applies for any "test that acts as a good proxy" for an IQ test, since if it does so it will have the same unequal racial impact (because if it didn't, it wouldn't be a good proxy) and, therefore, require the exact same evidence of predictive power with regard to job performance as a "direct IQ test". So the substitution you suggest achieves nothing.
Protecting against the "peril" associated with a "direct IQ test" isn't a matter of choosing a "good proxy" instead (since that does nothing to reduce the "peril"), its a matter of documenting the business justification -- the evidence that the test is a good predictor of job performance.
No, its not.
Like any input that statistically creates a disadvantage for any group defined by a protected criteria, it will, if challenged as discriminatory, require the user to demonstrate that there is sufficient evidence establishing that it is a reasonable predictor of job performance.
There is a pervasive myth that IQ tests specifically are "mostly illegal" in the US stemming from an early employment discrimination case in which the particular use was determined to be illegal, but its worth noting that in that case the IQ test was applied widely, it was part of a set of policies that were direct replacements for a policy of explicit racial discrimination (adopted once the company was subjected to nondiscrimination rules), and there was no evidence that could be offered linking it to performance in the jobs for which it was used. [0]
(It's perhaps worth noting that the case also addressed educational requirements -- the specific one at issue was a high-school diploma requirement -- which was found illegal in the particular use for the same reason as the particular use of the IQ test was, but for some reason no one has gone from that to adopting the idea that specific educational attainment requirements are generally illegal.)
[0] Griggs v. Duke Power Co., 401 U.S. 424 (1971)