Sure, there are similarities and coincidences between Greek/Roman history and Jesus' life. All religions are similar. But I think that saying that because they are similar they are somehow related is a little rash. I mean, look at Presidents Lincoln and Kennedy. I'm sure we're all familiar with their similarities. (If not,
Similarities Between the Assassinations of Kennedy and Lincoln - School for Champions: Succeed through Studying History ). But I doubt their was any conspiracy there.
I'm not saying that there is not direct connection here, just saying, it could easily be coincidence/proof that their were similar revolutionary ideas in that day and age.