Investing in Startups

Salaam,

  1. Is there any sharia screening criteria (debt and liquidity level, business operation, etc.) for the startups?
  2. If a startup offers to share only profit but no loss, is it a halal contract (Mudaraba/Musharaka)?
  3. Do I need witnesses before signing the deed?
  4. Is it compulsory to certify a company as sharia-compliant by a scholar or an Islamic institution?
    Can I invest if the startup is simply following the guidelines of mudarabah financing without the supervision of the sharia committee or certification?