This is one of those very specific situations, which is very dependent on the scenario. Athletes are admitted in ED2. It just depends.
At school 1, you do have a positive pre-read, but admissions assumes that you will have coach support. There is the legacy thing going on, but that only matters at schools that have made legacy an admission criterion (and often matters if the parents have donated). You should have a conversation with the coach to see if he/she will write a letter of soft support for her admission file. At a minimum, your daughter should ask what her chances for admission are without coach support, given the legacy situation. In best of worlds, the coach would ask admissions about her chances without coach support as opposed to guessing about those chances.
Then you need to have a similar conversation with the coach at school 2. Your daughter could say something like "I am a legacy at school 1, and my family wants me to attend. I have been promised a spot on the team, but the coach will not give me support. So, can you support my application in ED2? What are my chances of admission if I apply ED2.
In the end, sometimes it all boils down to information. If you can get a sense of admission chances, that will allow you to make the best informed decision.