An alternative plan that was floated but never researched in detail (AFAIK)
was to extend the DLR to Finsbury Park, using the Canonbury Curve - grade
separation for that would have been much cheaper. Such a scheme would be
impossible now, as the 'overground' will need all the capacity it can get
around there, leaving no room for a DLR track in the area.

Presumably, that would have extended along the NLL from Stratford?

Was there ever any consideration (whether seriously considered or not)
to carrying the Jubilee Line along the NLL route when it was being
planned?