Regarding the motor, 6 hp should be fine. I used to have a 1966 Evinrude 6 hp in my old Ariel. It was heavy-new motors are much lighter-yet moved the boat well even in stiff breeze and chop. Charging system for the motor is really not needed unless you are not in a slip with shore power. I have a charger mounted in my current boat that will fully charge the batteries and keep them charged. I moved my boat to New Orleans for about 3 months to race on Wednesday nights and didn't need to charge. Get a gel battery and you are in business.
Scott Shackelford
Ex-Hustler hull #223
Now-Sundancer
C&C 24 #232