Custom constituent header and GetConstituentInfoEx()

I may have just found the answer to my own question.  I hope it's right:

GetConstituentInfoEx() calls WP_GETEXTENDED_ACCOUNTINFO, which in turn calls AP_DONOR_HEADER1.  It looks like the process of creating a custom header does not modify either of these procedures, so I take it that hardcoded references to the default schema won't break when a custom header is used.

You are correct.  A custom header does NOT change the output of GetConstituentInfoEx

Thanks for verifying!