What is the ruling on the director taking gifts for herself that resulted from the work of the team members without their knowledge, and is it obligatory to inform the members of that?

If you are an agent on behalf of others in purchasing their goods, then the accompanying gifts belong to the principals (buyers) and not to the agent; because the rights of the contract pertain to the principal. You must return these gifts to their owners or seek their forgiveness for them. If it is impossible to explicitly tell them what happened, then they must be returned to them by any possible means, even if discreetly.