Pedal Steel. -
Lots of good chording and accompaniment real tracks to select from in BIAB.
That will give you a pretty good ideal
Alternatively/Additionally some of the LapSteel/Resonator Real tracks are pretty good.
You may find yourself mixing and matching to get the whole picture.
Be careful of how steels can clobber the banjo, especially the dobro.
Wait, I don't hear any banjo in there.
Aside- Perhaps some clawhammer would make it nice. Old timey vice 3finger roll sometimes gives you more of what you want.

The pedal steel is the string section of country music.

I play a few fiddle tunes at gigs and often add a pedal steel to the banjo/guitar/bass/mando ensemble.
I almost always use drums- much to the chagrin of some bluegrass purists.

I listened to your first track and think you might find the steel might work well
The fiddle just doesn't sound country enough to me. Sounds like a classical musician.

I use a lot of volume automation in the mix to swell the steel in and out.
Try a variety of real tracks, different takes. Focus on the accompanying real tracks, not the soloist.
You may have to do some cutting and pasting to get it where you want it.
It takes practice to keep it from getting too buy. Its a bluegrass band, not an orchestra.

Anyway, if you haven't tried it, perhaps you might give it a go

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