1. all steel hull and house; (this is good)
2. all electrical circuits fully grounded to earth TT (hopefully you mean at a single point not all over)
3. static dissipator at mast top (probably doesn't hurt but more likely better for keeping birds away)
Instead of the static dissipator you might consider a proper lightning protection air terminal. Make sure it is connected electrically to the mast with <1 ohm resistance and that the mast is also grounded the same way to the hull. The air lead should extend above other items mounted on the mast to protect them. If you are struck you want a clear path back to earth. Make sure your single point grounding connection of your electrical systems is robust since it may also be part of the lightning path through your hull. The preceding are a couple thoughts based upon some recent research I have done.
Isolation transformer(s) would reduce chances of galvanic corrosion and insure your system is always properly polarized regardless of what comes in. If you are using a 240 volt system you do not need to fear damage from loss of neutral from the pedestal since you will make your own neutral aboard. Better yet use an Isoboost type transformer to keep your power up when low voltage is all that is available.
General comments based upon your general question.
