This message is mainly for Stephen Hodge, regarding his work on the Yogacarabhumisastra. I was forwarded an email by Piya Tan, who i met recently in Singapore, and discussed my interest in such arcane matters. I'd be very interested to know of any research findings regarding the YBS. I've been doing some research on the origins of SA/SN and their role in the formation of the four nikayas/agamas.
My particular area of interest has been satipatthana, and i am endeavouring to collect all the available early material on the topic (and interesting late stuff as well). I read in a footnote to Analayo's book on satipatthana that there is apparently a version of the Satipatthana Sutta in the Sravakabhumi of Yogacarabhumisastra. Do you know anything about this? Is it in the portions of the YBS that are available in Sanskrit? If so, do you know the publication details?
Regarding the dates of EA/AN, the lack of congruence is not necessarily a sign of lateness. Other relevant factors are: EA is possibly from a Mahasanghika school, so the date of schism from the Theravada group of schools is earlier than in the case of the other agamas, so we would expect a greater degree of divergence. This criterion might be checked by detailed comparison of the degree of congruence of EA/AN, and the Theravada and Mahasanghika vinayas.
Another point is that there is a substantial amount of material in EA that is found elsewhere in the Nikayas, for example about 76 suttas in the Majjhima. This suggests that we have different sets of criteria as to what sutta goes where, that is to say, different editing policies, not necessarily later compositions. Again, there are several mini-samyuttas in the Pali Anguttara that in the Chinese are in SA (sikkha, kamma, dasangikamagga...), which is surely where they belong.
Having said this, i agree that AN/EA is likely to be, on the whole, somewhat later than the other collections, but perhaps not so much later as the degree of divergence may suggest. One of the surprising conclusions of the study of satipatthana is that the Maha Satipatthana Sutta of the DN is very late, possibly Sri Lankan, so there is clearly late material in the other Nikaya/Agamas, too.
Your statement of the influence of Yogacara on Buddhaghosa is interesting. I have noticed some similarities in the Pratyutpannabuddhavasthitasamadhi Sutra and the descriptions of nimittas, etc., in the Vsm; the PBS Sutra relates such ideas, at least in part, to the practice of satipatthana.