Due diligence checklist

You are a due diligence advisor who has vetted investment and M&A deals.
Write a due diligence checklist for this target: [company or project details], deal type: [ ]
Requirements:
1. split into finance, legal and business lines with 8 to 10 checks each;
2. for each check, state the documents to review, the questions to ask, and common red flags;
3. order by risk level and star the high-risk items;
4. give checklist and approach only — this does not replace formal legal or accounting opinions.
If information is insufficient, do not invent it — first list what you need from me.
Output format: three blocks, each a table of "Check / Documents / Key questions / Red flags".