Your friends might want to consider what the Chinese government might do if it finds them evading the firewall. Regimes that put up things like the Great Firewall aren't generally very understanding to people who evade their repression.
Your friends have to balance the desire for private communications against the possibility of getting caught and the likely consequences if they are caught.
I don't know why your friends are travelling, but if it's just for tourism, then they may be better off NOT to try to do any of these things, for fear of being falsely accused of espionage. The Chinese court system doesn't work like the US or European courts - it's quite heavily influenced by whatever the government wants it influenced by. So it's not like you can count on a fair trial.
I'd advise not doing any of the above and just hiding in the noise. Unless they are activists, your friends aren't likely to be bothered by the government. Why ask for trouble?