Marci, I'm just thinking here.
I would honestly not consider Layla a healthy dog.
She has a very hard time with vaccines and anesthesia (reason enough to BAT).
She has lots of GI issues and sensitivities which can indicate a problem sometimes.
And then the LP which would be unrelated but it is still a problem.
It sounds like you have a lot to think about to take care of her.
Maybe we should have a "My Yorkie has issues and my head is spinning club".