It's been over a year since I read anything about early Christian history. But since we are talking about the first few centuries (possibly until 325 AD, and things were brutal in the latter tears), I think the title of Christian was established, embraced by Christian's, and despised otherwise. Though I could be wrong.
But point one is clearly true... Perhaps they were not calling themselves Christian's, but they were pretty steadfast in their beliefs. So much so they literally begged to be Matty's at times, according to the last book I read.
Point two is perhaps the strongest reason, and the same reason Jews were persecuted. The law of our God dictates not to even acknowledge other Gods (Caesar, Jupiter, Zues or otherwise). Jews and Christian's shared a common belief:. There is only one God.
The Romans, like Alexander the Great, were very tolerant of other religions. They only asked that other people acknowledge their God's. That's easy to do when you have a Sun God, A Hell God, a Sea God, a love God, a harvest God, a wine God, etc...it's easy to say well, you call the head honcho Zues, and we call him Jupiter.... You have Venus and we have Helena... You have Mars and we have Aries... On down the line. But when a couple of folks (Christian's and Jews) say, "No, their is only one and all your God's at B.S.... they got offended.
So in short, Christian's and Jews refused to acknowledge other Gods. The Romans didn't have a problem acknowledging Jehovah, but with the practice of "spitting" on the belief that other Gods.
As for the third part being an economical problem... I don't think so. Not in the way it is presented. I think it was a problem that they WEREN'T sacrificing (when the Romans wanted them to). The Romans were also probably offended that Christian's were vocal in their disapproval.
But there weren't that many Christian's in that day. Not enough that it would sent the economy of meat sells for sacrifice.
Idols, maybe... Paul preached against them and the makers were so outraged they had him arrested.
There is another theory, and that is the bizarreness of Christendom and misunderstandings. I have read that many believed Christian's were into human sacrifice, cannibalism and blood drinking. Well... There is reasons for these misconceptions. But rumor Mills tend to distort truth.