Is it Islamically permissible to offer a bus valued at 200,0 dirhams for Mudarabah, Murabaha, or as a pledge, whereby someone gives this amount in exchange for temporary ownership of the bus for one year, benefiting from its revenue, and then the bus is leased back from him for 20,0 dirhams annually, payable in installments? And is there any suspicion of Riba (usury) in this?

This transaction falls under the ruling of a loan that brings benefit, and every loan that brings benefit is usury (riba). The correct approach is for the owner of the money to enter as a partner in profit and loss. The consideration in contracts is based on meanings, not names. It is not permissible for the mortgagee (the owner of the money) to benefit from the mortgaged item (the bus) if the mortgage is in exchange for a loan, because in that case, it would be a loan that brings a benefit, and that is forbidden.