Financial lease is a leasing transaction, where the cost of the vehicle and the interest are divided to equal instalments, with an agreed payment plan. After the last installment, you will become the owner of the vehicle.
Operating lease is a leasing transaction, that allows to use the vehicle for an agreed period of time. It is however possible, to buy out the vehicle after the end of the lease period.
In case of a new car minimum 10% of the car price; in case of used car down payment is usually more than 10% of a price. Higher down payment reduces cost of interest and therefore monthly payments.
The higher residual value, the lower periodical payments, but the higher are costs on interest. Maximum residual value is dependent on duration of the lease period. E.g. in case of 3-year lease period the residual value cannot exceed 45%, in case of 5-year period 30% etc.