Good and Evil CharactersFollow

I'm brand new to the game so I have some questions. I've been able to find a lot of information online -- thank you Internet -- but can't figure this one out.

My main character so far is a high elf aligned with New Halas which apparently means I'm a good character. I'm interested in making an evil character alt. If I do that and make them on the same server will I be able to trade items between the two toons? This is important to me because I don't want to start from scratch again.

Secondly, if I make a neutral character and align myself with one of the evil cities will that automatically make me evil or do I remain neutral?

And finally, how does betraying your city work? If my evil character cannot trade items with my good ones I might consider betraying my city and becoming good. How does that process work? Is it worth the effort and how time consuming it? Then once the transition is complete will I be able to trade items between my good character and this one? Alternatively what if I decide to stay an exile, will I be completely on my own then?

Thanks so much for the help.