It's definitely an interesting idea that they might be related. I'm not sure if I'll give Squeenix that much credit any more, though...but then again, one can never underestimate the power of Nomura's mancrush on Gackt and his trying to shoehorn in Genesis as a crazed Gary Stu. He's Seph's rival! And Aerith's half-sister! And all the SOLDIERS love him and become his clone willingly! And he doesn't die! Oh, Nomura. Just buy him some chocolate this Valentine's Day and confess your love to Gackt already. XDDD
And hee--Jenova IS a space virus. Does this make Seph a Trojan? *is shot*