On the first point
[C]ritically, the plaintiff's own lawyer argued that if the restraining order was not granted, then legally there was unlikely to be a case for a retroactive decision.
Brunn Roysden, acting for the states, described the transition of the IANA contract as "just like the case of a bulldozer about to demolish a historic, unique, important building." The harm, he said, was "imminent and irreparable."
The attorney had to argue "imminent and irreparable harm" as it's a requirement for the granting of an injunction like this. But he is free to now argue the exact opposite - i.e., that the court can order a retroactive invalidation - and these statements can't be used against him. It may seem odd but it's a function of how the US legal system works. Attorneys are advocates, they are expected to provide every remotely reasonable argument on behalf of their clients, even if the arguments are contradictory or mutually exclusive. It is the job of the judge (and jury to the extent applicable) to review each argument in isolation and determine which, if any, have merit.