Well, it was cut out of the movie but technically Tom was not a consigliere until that night when Genco the old consigliere died.

As for the abortion, it happened during the time Kay was not even allowed to go shopping, so I am sure someone must have taken her to the doctor (for check up I guess). I always wondered how did she managed to get to a doctor who did not know her, and if the doctor knew her which suicidal doctor would have done it. Maybe she picked a time when Tom was away getting the senator stuff done for instance.

Technicalities do not matter though- it is one of the most powerful part of the movie, it has to happen, and since Tom survives, it seems that Michael ends up blaming only Kay and probably himself.