I suggest you call and ask to speak to either the dean or the admissions director. Explain that you have an emergency situation involving an exploding scholarship at another school. If you can't get through, talk to whoever they allow you to speak with AND follow up with an email to the dean and/or director. You don't have time to mess around!
No, your WLs will NOT be automatically purged by the system, but, starting on 4/30, your WL school will be able to see the CTE and is supposed to drop you if you have not already withdrawn (which you are also supposed to do, and which is what your scholarship school is specifically requiring you to do). You NEED to get this straightened out with your WL school before 5/3.
These are your possible outcomes: (1) they accept you off the WL and you drop the other school; (2) they assure you that they WILL accept you off the WL, and you don't CTE to your scholarship school, just remain PTE, and let them rescind the scholarship; (3) they tell you they don't know what's going to happen with the WL, but they agree to allow you to remain on the WL while being CTE at the other school, in which case you CTE to the other school and wait to see what happens; or (4) they tell you it is unlikely you will be called off the WL, or, they tell you nothing but you cannot remain on the WL while being CTE elsewhere, in which you tell them thanks for nothing, withdraw from the WL, and grab the scholarship.
There is, of course, a 5th option, which is turning down the scholarship while remaining on the WL with no promises from the WL school, but, under the circumstances, I don't think the risk of never receiving the call off the WL is worth the $60K, especially after spelling all this out for the WL school and having them do absolutely nothing for you.