Let's say we have a MAST with n scripts in the leaves, is it possible to require that two (or more) of the scripts must be revealed for the transaction to be spent?
With Taproot no it is not possible. Only one leaf script in the Taproot tree needs to be satisfied to spend the output and you cannot require the satisfaction of multiple leaf scripts to spend the output. The Taproot tree has the equivalent of OR statements between each leaf and you can't use AND statements between leaves. There are alternative MAST designs that have not made it into Bitcoin at the time of writing (November 2021) but the above is the case for Taproot's variant of MAST.