Yes, there is a risk that some persons would consider that offensive. A lot depends on context, like whether the person in question is your friend and you know he is not offended by it. But walking up to a Latino stranger, while in an English-speaking area, and calling him “amigo” might be regarded as offensive either because (i) it places inappropriate emphasis on his ethnicity, or (ii) it assumes, without evidence other than his appearance, that he is a Spanish speaker.

No, amigo (used for males) and amiga (used for females) is a friendly term. There should be no offense taken if you are using it in a friendly way. If you are angry when you say it then yes, it could be offensive. Friendly: OK amigo, I’ll talk to you again later. Unfriendly: Hey amigo why don’t you watch where you’re going? You almost knocked over my kid, you jerk!

Not racist per se, but just offensive. I am latino myself and I hate when people call me like that, it may sound like they are mocking at you.

Context!

it is considered racist (period). Only ignorant people make racial slurs to address others. Everyone has a name, you can simply just ask What is your name?, and then proceed with "hey, Jeff..." but no you choose to address someone with a racist slur and quite frankly you deserve to be slapped.