Make sure that you keep a good eye on the sacraficial anode on the outboard. These are cheap to replace and it is designed to 'sacrifice' itself to protect the outboard. If you are worried about galvanic action when plugged into shore power, then disconnect the charging circuit from your engine when tied up alongside (or fit a two pole switch). If you do not have a charging circuit then your engine should be isolated and cannot act as an anode, marina's earth acting as the cathode, sea water as electrolyte ( I think thats how it works).
Not sure about antifouling the outboard leg. We have been keeping Ladybird in the water at a marina for two months at a time (2 month in/2 month out). Any small barnacles that form can be wiped off. But I have noticed that the anode wastes away quickly.
We are also thinking about Coppercoating, it will be a better solution to the drying out periods. Just not looking forward to removing the old coatings.