I believe Benfica would play on the Thursday, and Sporting on the Weds (or possibly Tuesday) as Benfica are, I believe, the "first team in order of priority" - see rule 6.1 (and 5.1) of https://editorial.uefa.com/resources/0283-1890ff52a70b-8834be495fc4-1000/city_and_stadium_clashes.pdf
Based...