In the first shot, Heidi looks similar to another scene in ep 2 (post #150096) which I'm 99% sure is Okada (although in both cases, Heidi's somewhat different look could be Kotabe's corrections, I'm really not sure).
Moreover, since the 2 others animators of the ep (Kôichi Murata and Toshitsugu Saida) were from a different studio, I don't think it's too far-fetched to presume that they animated a different half of the episode. If that sequence *is* Okada, then it probably means that all the B part of ep 1 is by him