Lahree, the link you posted is really good information and sounds like it fits your situation with Ellie to a 'T'. I also highly recommend Patricia McConnell's book. I haven't read that specific one, but everything I've ever read from her is spot on and takes the dog's point of view into consideration.
There's great wisdom in your decision to avoid the trigger situation for a good period of time. Use that time to continue to develop your working relationship with Ellie and sharpen your observation skills and reaction timing.
It's not exactly the same thing, but Phebe is a very responsive dog on the Agility course. Pair that with a handler who has a very low body awareness (some people refer to it as klutzy

) and you have match made in hell. I've learned more from our mistakes than I'll ever learn from our successes. I have to always remember that her gas pedal and brakes require only the lightest touch and her steering is like that of a Ferrari. If I can just learn to make the top half and the bottom of half of my body say the same thing all the time, we'll be golden.
Does Ellie ever tug? If Phebe were acting like this, I would be tempted to put a tug in front of her face when she escalated and then engage in a brief, but satisfying, tug session. My goal would be to move her focus from the other dog to me and still give her a physical outlet for any frustration, fear or aggression without a fight or flight response.
This is just me thinking out loud -- so don't take it as anything more than that.