Are taking a pillow and a blanket found in the street, as well as biscuits found near the Jamarat, considered part of the forbidden lost-and-found items of Mecca? And what must be done if that is unlawful?

The belongings found are considered "Luqata" (found property) and are subject to its rulings. If the item is insignificant and of no value, there is no harm in using it without announcing it. However, if it has value, it is obligatory to announce it for a year, or to hand it over to the responsible authorities in the Haram (Grand Mosque area), which absolves one of responsibility. The same applies to biscuits: if they are few and insignificant, there is no harm in eating them. Otherwise, if there is a fear of them spoiling, the finder is given the choice between donating them as charity or eating them and guaranteeing their value.