I believe that SYA will absolutely help your daughter in the college process. There are many, many kids who stack up AP classes junior year but very few who are brave enough to take the risk of leaving their high school to study in Spain for the year.
The SYA program is rigorous and the students come back fluent but also with incredible knowledge and deep cultural understanding. They learn about the history, art history, government etc of the country. And all while staying on track with math and English. And most kids will take a few APs (usually English and Spanish and maybe math).
My son also ran with a cross country team after school and made many Spanish friends that way. And through his host family. Yes, they are not in a Spanish school but they have the best of both worlds - they stay on track with their home HS and the are immersed in life in Spain.
My son participated in the program last year as a junior and I am happy to answer any other questions. He is still waiting on some college decisions but had already been accepted to some top schools.