What ships dock there? At a guess - is it
Disney lines only? It's too bad the QM2 won't be able to 'park' next
to it's famous older sister - that'd be quite a sight! Perhaps the QM2
can't dock there, due to it's size? And, is it true the QM2 is too
large to go thru the Panama Canal?

I think that only Carnival Corp ships can dock there as Carnival paid for
the facilities. That means that the QMII can dock there if there is room.
Carnival owns Cunard. OTOH, the size of the QMII may prevent that.