I have so little to offer in the way of Bluegrass .. I don't even know the rules.
But this one time, just for fun, I was testing Reatracks to see what would happen if I mashed a whole bunch of different styles up to create a new 'thing'.
I ended up with this mess .. but all the Reatracks basically cooperated.
Choosing a Grunge drum (forbidden in BG), Funk bass, mandolin, banjo, harmonica, and random other stuff ended up like this -
http://bobandbarryshow.com/wp-content/uploads/2021/10/Urbn_211024b.mp3

Lots of surprises, and they keep time well, but pretty much 'soup' if you are looking to do something in a certain genre.
However BG Realtracks are in there..
/My goal above was to do something totally outside the box, and I think I succeeded (though outside the box isn't always better).
//not sure if that helped anyone (or ever will) but there ya go

I do not work here, but the benefits are still awesome
Make your sound your own!