Huh... my sources state the Omophagia was a symbolic meal of raw meat and wine.
Checking my sources, it seems like the Orphic followers of Dionysus, at least, were the ones that did the practice and used raw meat. They're also the specific sect that believed in his death and resurrection, but they explicitly believed Dionysus' mother was Persephone, a goddess.
This is incorrect. The Orphics probably wouldn't have used raw meat as they were vegetarians - shunning the more traditional, corporeal cults as barbaric. The tale of Orpheus' death at the hands of Maenads - Dionysos' more traditional followers - is probably designed to emphasise this difference. If anything, the Orphics were more likely to have bread as a central part of their feast over meat. Also, the Orphics believed Persephone was
one of Dionysos' mothers. One of the god's epithets (that the Orphics as well as others used) is
Dimeter: 'of two mothers'. The Orphic Hymn to Semele calls her:
"... fair Semele of the lovely tresses,
of the full bosom,
mother of thrysos-bearing,
joyous Dionysos."
Also, the belief in his death & rebirth was not unique to Orphism as you allude. Dionysos' mysteries at Delphi, for instance, held a set of myths associating his dismemberment and planting of his 'parts' as the winter and spring festivals respectively. Other cults would have associated his epithets
Meilichios and
Bakcheos with the cooler and warmer weathers specifically due to the latter's associations with fire as well as Dionysos' syncretism with Sabazios; a Thracian/Phrygian god strongly associated with beer and fire. This would have strengthened the god's association with the annual cycle from winter to summer back to winter, repeat ad infinitum.
So it seems to me like the similarities are only strong if you take specific elements from different Dionysus Cults and ignore other contradictory elements, and combine the beliefs of different cults together.
I agree. Dionysos is only similar to Jesus if you view him through Orphic eyes. Indeed I think Orphism, though it had died out by the time of Christianity, wouldn't seem all that alien to us if it were revived today exactly as practised back then. If you view him in the more traditional sense, however, there's too much spilled blood, wine and torn flesh between them to make out more than a passing similarity.