Question: Calls from abroad

Im thinking of getting a US or Canadian number through JMP Chat, to use with Cheogram for my personal Calls and SMS... (i dont use sms, just need to receive verification codes sometimes)

• I understand i can call anyone even if they have a normal number from a Latin-american country code (not VOIP) (after adding them properly with the _number_@chatterboxes.com) Is this correct?

• Do roaming charges apply to them for calling to a US/Canadian number? (or to me, vice versa?) Does it depend on the carrier's plans from my country?

• What's your opinions of the Twilio SGX for these scenarios?