I read somewhere that the vote happened without Greg being present. I wonder if all 4 members present actually voted to oust Sam Altman or if atleast one of them voted no.

It will be a bit tricky getting the information but in case it somehow becomes public through credible reporting (e.g. theinformation) or non-conflicting statements by the 4 members who were present.

Here is a list with everyone who is or was on the board of directors of OpenAI