The colleges with “the BEST chance of admission” are the colleges where SHE matches what THEY want. Not the general admissions rate. Have you explored what her real match is- not just stats and some ECs with leader positions. It’s the rest that matters, when these are competitive holistic schools.
The problem with trying to game this is the fact of making this decision now. There is no advantage to an early app, “just” for applying early. You have to be what they want.
That’s one of the important elements we considered when each kid made her choices: “They would want me because…”