Paul was not a Jew persecutor, and neither does scripture state that. You are simply making things up. Scripture states that Paul, being a Jew himself, persecuted a sect of Jews (the Jesus movement). He was hardly the only one, and there is good reason why other Jews would have persecuted that sect. It was dangerous, and it was seen by many as being wrong. To what effect Paul persecuted those members though is not completely apparent.
Paul was never a Roman though. There is no evidence he preached to the Romans, unless you consider everyone in the Roman empire to be Romans (which would then mean Jesus was a Roman), but that simply is an illogical position. Paul preached to Gentiles. Gentiles do not equal Romans.
Also, Acts states that Peter preached to Gentiles as well. Paul even states that Peter mingled with the Gentiles too. So your argument there fails.
As for real scholars who don't think they were enemies, Bart Ehrman, Marcus Borg, Pamela Eisenbaum, Amy-Jill Levine. Should I go on?
Why don't you support your claim and show some scholars who think that Paul and Peter were enemies.