Also, businesses making claims in the liquidation should be doing so as businesses and not as individuals. So at least claim as "Joe Smith trading as Bitcoin Scam 5" instead of just "Joe Smith" - otherwise there are going to be even more legal shit-fights.
What you say is correct but it has significant practical implications, in the sense that if he does claim as a company the fiscal authorities in his country will probably regard the entire thing in such a light as to give him decent odds of an unsuspended jail sentence. So he won't be doing that.
Nowhere would you get interest just for owning bitcoins instead.
You're wrong. And iirc this was available
since before Bitcoinica.