No and no!
The new base would be market sensitive data and therefore it is highly unlikely that any cabin crew members that browse PPruNe would be aware of this information.
If any members did announce details of a new base ON HERE prior to any official announcement, they would have to hope that nobody knows the person behind the PPruNe identifier, as they would be commiting gross misconduct and effectively giving themselves the sack.
All crew are issued with a little card which states "I'm sorry but I am not the person you need to speak to and have no information that I can give you" - the quoted text applies on here for your question.