Is there any doubt concerning the acquisition of a car and its rental to a specific individual for a predetermined monthly fee, with prior knowledge that it will be rented?

There is no objection to you agreeing with your friend that you will buy a car and then lease it to him under pre-agreed conditions and regulations. It is permissible for an institution to purchase the asset that a client wishes to lease, and the lease contract can be concluded directly or a general framework for the agreement can be organized. It is also permissible for the lease to be for a described asset that is not yet in existence, provided it is precisely described, even if it is not yet owned by the lessor, taking into account the lessor's ability to acquire or manufacture it.