A fuse is usually installed at the battery, this controls lights and accessories. replaced mine a few times, also there is a fuse under the cowl on outboad motors that control the engine start , that may have blown. google your motor brand and you should be able to locate the fuse.
Under boating regulations a " soul " has no weight. this means a 500 lb person or a baby weigh the same for the listed 15 person limit. The boat structure would be a whole different issue as to the total weight of passengers and equipment.
I had these on my trailer when i was still towing the boat. i am on a lake with 10-15 mph. crosswinds and never had an issue. once the boat starts on the trailer I could power all the way and it would center on the bunks.
I replaced my door a few years ago, the rivets can be drilled out and the same holes used for the new ones. i drilled the ones out of the door, new hinges do not come with the door. You may want to ask your dealer or Bennington what size rivets to use. I can't remember the size but I know it was...