It may sound ridiculous, but it is the strategy Ritz implemented in XC - and it worked, as he broke Webb during the third mile to run away with the title by 20 seconds.
Just to reiterate the similarities between the situation... Efraimson, like Webb, has far better footspeed and far better potential at the under distance events. Anna Maxwell is the only athlete in the field with anywhere near the same mix of speed and endurance.
But here's the bottom line:
If you're going to beat a better runner, you have to attack their weakness. The kick certainly isn't Efraimson's weakness - it's her strength (see NXN). She's shown she can get pulled to fast times with her 4:32i mile and her 9:00i 3k. What you also saw in those races was that she couldn't win. And she almost broke at NXN as well. And each time, she lost contact around 2/3 of the way through the race - she might have closed as fast, or faster, in each race, yet she was gapped. In the 3k, it was just after the 2k mark when the leaders took off - and Efraimson didn't follow. In the mile, it was just after the 1200m mark when the leaders took off - and Efraimson didn't follow (and they were going through in straight 70's to that point, it's not like she couldn't have tried to go with them). At NXN, it was just around 2.5k when she started falling off, though she surged back to the leaders by 3k but it was clear she was starting to struggle to maintain pace with them by that point already. Clearly, this is a trend. It's what Alexa probably needs to work on the most when it comes to racing - being able to stick with people when they make a move mid-race - and until she has shown the ability to stick with strong mid-race moves, that is a weakness.
So why would you attack her strength, when you can TRY to exploit the perceived weakness, as shown in both her best races and her solo efforts (she has tended to lag in the middle, like many racers, when she's running on her own). If she's going to get broken at any point in the race, it's when someone makes a big enough move in the middle of it and she doesn't respond quick enough. So that is the logical point of attack for any real contenders.
I can't speak to your math - I am not going to put a specific time on how much chasing will help Baxter, or leading will hurt Efraimson, or whether or not Efraimson would have finished in 9:40 against any competition at the UW Invitational. And I will be rooting for Efraimson in her race. But if I was her competition, or a coach of her competition, I'd be thinking about how to beat her - and the best solution I can see is to attack mid-race and try to break her there, so she won't be able to outkick me or my runner to the finish, and so you don't bite off more than you can chew too early (by blasting from the gun). But that's the key to racing, isn't it? Finding just the right time to make your move, and then make it decisively enough that you aren't countered.
That's what Ritz did at Footlocker in the example I gave. No way of telling if it will work, but it seems like a good plan to me (and seems like conventional wisdom, if you are facing someone with a better kick).