Hi,
1. I’m afraid no – that feature is fully hard coded, it can’t be invoked via a hook. How does the advanced content field look like? Can you please copy/paste it here?
3. Only by completely reworking the statistics dashboard. We have that planned, so it will be available in one of the future releases.
4. You can try to custom code that via the asp_results hook – however I don’t know if I recommend that. Requesting the fully filtered post contents each time, then possibly doing DOM manipulations via PHP to detect where the text is – that may cause a lot of server overload and decrease the search performance. There is no generic solution for this I can suggest, it has to be custom coded for the exact page output.