arduino & drivers to control 5 brushed CIM motors independently?
You should have just enough I/O with UNO, so long as you don't want to connect any other hardware/sensors.  Since this is unlikely, it would be better to use another board like Mega, but I'll provide solutions anyway in case you want to try them out:


Option 1:  For 5 motors controlled with L298N boards you'll need 15 output pins, 5 of which should be PWM.  Fortunately, there are 5 PWM outputs on the Arduino UNO on PORTB and PORTD.  The remaining 10 outputs need only be digital (PORTB has 1 and PORTD has 5).  You can use DDRC and PORTC commands to change function of the analog inputs labeled A0-A5, making them digital output, thereby gaining 6 more digital output pins for a total of 12 (more than the minimum 10 needed).
Option 2:  It is possible to use other PWM motor drivers that reduce number of pins required.  Examples are DRV8838 (link to supplier) and DRV8833 (link to supplier) where 2 wires are needed per motor channel.  As a bonus, these drivers are also significantly more compact than L298N.