YES the domains in question could have been cancelled before landrush.
The Agreements give Afilias the power to cancel and delete names, particularly, but not only, in the event that any of the required data fields are not provided.
The excuse that Afilias gave at the time for NOT cancelling the names before Landrush was that they did not want to damage the process, because it was meant to be "proof of concept".
I regard that as laughable, as the process had already been damaged, both by Afilias's failure to enforce the Sunrise rules, and by abuses emanating from WITHIN the industry, and even WITHIN Afilias.
I should have thought that protecting consumers and doing the right thing was more important than the proof of concept, and besides, the rules within that proof of concept DID grant Afilias the power and right to delete names.
They just chose not to.
As to the matter of whether they cancelled any other names before Landrush, I cannot recall without checking my archives, but from memory I don't recall any names being deleted.