Re: modify Featured Members widget on Members page
The long term solution would be to have them add a filter, so you can replace the standard function with your own.
https://codex.wordpress.org/Plugin_API#Filters
Their may already by a filter in place you can use, which would either modify the output of a function, or replace it’s output all together.
The other option is to just write your own widgets, You can see what I did, it is a basic copy of the default members widget with a little customization for my needs:
http://gorgeousgamers.com/beta/
By writing my own widget, I can bypass those functions and just make my own, for example, I may only want to show popular members which don’t have gravatar avatars, would be very easy with my own sql calls.
Let me know if this makes sense,
Brad