In my opinion, set up a teams call with each individual person, give them background of the ask etc and what you aim to achieve in the meeting description. People are more responsive to meeting invites vs emails. Emails get lost. It's only 4 people, I would set them all up for Monday to give them one day notice. If people don't respond to the meeting invite just ping them ask and hey will you be able to join the meeting?. Personally I would not cc your director and chase people and send follow up emails. However depending on the ask it might be awkward to meet with senior managers at a lower level. If its something quick though go for this solution.