Oh and taking the wife is essential as you mentioned in the past ! It's a prerequisite for extending this visa but also very helpful for communicating exactly what they need and how to get it.
You only need to embassy letter for the 30 day 'amnesty' extension
You don't need it for the 60 day family visit extension (but will need other documents which you should get a list of)- this is probably the easier and better option for now.