Bear in mind a crytographer is involved in Shadowsend, Techovert. If, as you say, ssv2 is an implementation of cryptonote, then why would Ryno collaborate with him? Ryno certainly has the skill to build an implementation of cryptonote without any help
I'm not familar with this technovert. What else has he accomplished?
Assuming your developer is not a cryptographer and employed the assistance of one, that speaks well of him. There are certainly aspects of shadowsenc that are different from cryptonote (such as the way it integrates with the non-anonymous SDC), and any changes or differences in context should be reviewed by a cryptographer, yes.