Peter, do you know the source of the quote that aikido should be practised against a single opponent as if you had multiple attackers, and vice versa?
No, I don't. I am hopeless with quotes, especially from people like Morihei Ueshiba. However, I believe that Okamoto-San and I share something of a common lineage, in that we both took classes from a wide variety of teachers. Tada, Yamaguchi, and Arikawa regularly came to Hiroshima and I had the benefit of some years in the States with Kanai, with regular input from Yoshimitsu Yamada, and then with Chiba in Japan. To name just a few.
So I would not want to say bluntly that Okamoto-San's footwork would not work, since I am quite sure that she has the resources to make it work. Actually, I tried it tonight in a class. I could make it work with one uke and also with two ukes, but my own personal preference would be for the regular footwork. This being said, I suggest that you try dealing with four attackers, all holding with morote or ryo-kata-dori. You can do it with two attackers, either holding left and right, or front and rear, but it is more difficult with them attacking all together. I had to do this for my shodan test, in 1978.
Okamoto-San showed her interesting footwork with one uke, but I think that morote with two to four ukes is a very good training method. I am in my seventies, and I cannot use pure physical strength, so I have to use my entire body-mind, in ways that I still do not fully understand. Had you started training when M Sekiya spent his year in the UK?