I'm in agreement with ryan, however I'd go one step further with this charging jack and just do what most of us do. Most people dont like leaving the battery in the boat since there are fire hazards, however we could leave in the boat and just hook unplug the batteries from the esc and plug the battery in the charger. You dont have to take them out and I admit sometimes I just leave them in since I'm lazy and comfortable with my charger and batts.

If I may ask, what do you need two servos for?

Also you dont really need an on/off switch, I've never used one.

I modified your diagram to reflect what I'm suggesting
definitely use deans connector throughout as ryan suggested