Insurance, the devil is in the detai, which you often don't find out until its to late. Based on my experience, 3 & 5 and probably 2 are the same thing. 4 should be covered by the club insurance and that is one of the reasons such events are members only. I am not in any Porsche Clubs but TVR and Triumph covered you for club events if you had the "club" discount from a club approved insurer. Covered me for Grand Prix circuit at Brandshatch and Milbrook Proving ground.
Ask how comprehensive the European cover is. That could be a bit of a surprise as well.