I was watching a video of a Vigil service at Vatopedi monastery on Mt. Athos (at least that's what it looked like; I speak no Greek). I was somewhat surprised to see what looked like Russian vestments on all of the clergy: all the priests had high-backed phelonia, and all the deacons had single oraria, instead of automatically getting double ones regardless of rank. Do all clergy on Mt. Athos wear this style of vestments? Are high-backed phelonia older than low-backed, fitted ones, and if so, when did the change happen?
Don't quote me on this, but I read somewhere that the use of "Russian vestments" in Athonite monasteries had to do, at least in some cases, with the fact that they were gifts from Russia. The Russians gave what they knew, and the monasteries put them to good use. Did that inspire an "Athonite" style of vestments somewhere down the line? It's possible, but I can't say. I'm not sure, though, that "high-backed phelonia" are older than "low-backed phelonia". It would be interesting to find out if older icons provide a clue.
I suspect, though, that some usages are older. For example, I think the single orarion for deacons (as opposed to the double oraria in use in modern Greek and Arab tradition) is definitely older: it is common to the diaconate in Slavic Byzantine, Syriac, Armenian, and Roman (and other Western) traditions.
Another thing I noticed was that some of the priests had stoles that were all of one piece, rather than being divided and buttoned together, which I thought was interesting since that's how Oriental Orthodox stoles look, apart from Ethiopians who seem to have adopted the divided stole as well.
The "one-piece" stole for priests is a predominantly Coptic and West Syriac practice. Ethiopians may use both forms (I really don't know), and I'm pretty sure I've seen Armenians use both forms (though I'm not sure if one form is more common).