A couple of question for EB multiplayer

[TwoKnives]

Hello, I'm a new EBO player and I got a couple of questions about the factions:

1.Which is a good barbarian faction that is easy to use for beginners?
2.Which is the best faction that can be used to counter Rome?
3.Which is the best tactic (if any) to counter phalanxes when using barbarians, aside from flanking them?
4.Is there a worst faction?

Thanks in advance.