Your lead internal auditor will likely set the requirements to BE an internal auditor. Then you will need to document the education/training/auditing that has occurred for each auditor in ISO or MSA or auditing principles, etc. Add in the time they spent on gap analysis from TS to IATF, toss in the time they spent on
APQP teams working on the
FMEA's etc. Talk about the time they spent with consultants or other internal auditors defending their gap/FMEA's/audits. Explain that all the audits counting toward IATF were done to the new ISO/IATF clauses. Show your CB auditors that you are using these tools to evaluate their competency.
We passed our IATF16949 audit in June.