like i said theory that started only by thinking about jutsu. no basis, as stated in op. i do believe, however, that kishi has left enough open plot room re: oro to drop a bomb like that.
consider: during the Pain Arc, no clues were ever given to suggest that Nagato is Uzumaki.
Oro has never been designated a last name, clan or parents in the series yet he uses a sage technique (no Uchiha have used senjutsu of any kind; for that matter, no one other than those related to senju in some way have used senjutsu/ yes, i know senju and senjutsu have different meanings in japanese)
also, kishi obviously has some major role for this character
still, while i have no facts for the theory (which is why it's a theory i'm investigating), those against this idea also have no facts against what i stated in bold (other than fanboyism, which is not a debate)
thx for worthwhile participation and discussion btw Psyduck. ur debate is helping me to clarify this idea in my mind