That's up to you. I personally hate putting dialogue in colored text, but I'd be more than happy to do so if it would be easier for you to understand who is talking. But I definitely like the bold text for when they're texting or messaging. Perhaps we can put those messages in quotes and if it's online, have their username in front?

For example:

[b]MysticDirector:[/b] Yo.
[b]Darkwolfgirl:[/b] hi!

And so on and so forth.