I would collect the information under the requirements of Reg B 1002.13. If you note in the Commentary to 1002.2(f) it states the creditor has the latitude under the regulation to establish its own application process and to decide the type and amount of information it will require from credit applicants.
IMHO a pre-qualification application is a request for credit. It's just that certain regulations excludes them from their definition for disclosure, notification and/or reporting requirements.
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The opinions expressed are mine and they are not to be taken as legal advice.