Class 100 cleanrooms are often called ISO 5 or Grade A/B cleanrooms (newer standards and guidances). A good guidance for what tests need to be done to certify the room is in ISO 14644. There are required tests, and optional tests highlighted, with the required frequency and acceptance criteria. Most world-wide guidances (like the world health organization) reference the ISO standard, although the EU has slightly different acceptance limits.
Yes DOP (aerosol) tests do need to be done to certify the HEPA filters, and typically that is done in OQ.
Also, a typical air flow for HEPA filters is 90 feet/minute target, and is typical and expected in industry.