Different shops of the same telco will tell you about different plans, but 8RMB/month basic fee is fair. Cheapest way to add data is buy a card on TMall, if you can manage payment and read Chinese.
And yes, enable international roaming and receive texts free. Useful for banking and such.
Yes that is a good plan. They tried to kill it recently and move all new users onto the 16RMB/month plan but thankfully it didn't work out.