Multicultural groups are wonderful that way because some of the differences are just fun and you can adopt them because they're fun and/or different but some of them just make more sense or are more comfortable. Add constant threats of death and destruction and you start using whatever works.

I think the conversation about America's Most Wanted and terrorists and such would probably involve someone pointing out that the SGC are pretty much terrorists on the galactic scale. After all, they are sending out small groups to attack the established governing bodies of the galaxies. The fact that the established governing bodies are made up of slave-taking snakes, soul-sucking vampires, brain-washing priests, etc, doesn't change the methods used by the SGC after all.

There are a variety of fandom explanations for why Daniel didn't go to Atlantis (mostly involving relationships with Jack), but I think Methos and Daniel knew each other before all this. I'm not sure if Daniel tracked down Methos or if Methos showed up on Daniel's doorstep, bored and looking for something interesting to do. Whichever happened though, Daniel realized this was a golden opportunity and offered Methos the use of his identity. Then it was just a matter of Methos calling up the recruitment people and letting them know he was interested after all. The SGC probably had Daniel do the job interview, too.