Google Sheets INDEX-MATCH Setup

I have a Google Sheet that relies on data look-ups across several tabs. I’m comfortable with basic SUM and AVERAGE functions, but the sheet now needs smarter, more flexible look-ups and I want to transition from VLOOKUP/HLOOKUP to an INDEX-MATCH approach.

Your task is to review the existing workbook, identify where look-ups are required, and build reliable INDEX and MATCH formulas that return the correct values even if columns are moved or new rows are inserted. I’d also like the formulas to handle common edge-cases such as blank cells or missing keys without throwing errors.

Deliverables:
• Fully working INDEX-MATCH formulas inserted in the sheet wherever look-ups are needed.
• A concise, in-sheet note or separate doc explaining each formula so I can tweak ranges later.
• A quick accuracy check (spot-test a few records) to confirm everything pulls the right result.

If an ARRAYFORMULA or another function would make the setup more efficient, feel free to suggest it. I’ll share the sheet once we start; it’s under 5,000 rows so performance isn’t an issue. Looking forward to a clean, well-documented solution I can maintain going forward.