Yale has over 5,000 undergraduates, and I imagine about 10% to 15% of them are involved in either acting or singing. So, if you want to be surrounded by actor/singer types, then you can find certainly find that at Yale. But, if you don’t, there are many other options: https://apps.students.yale.edu/uor/RegisteredOrganizations. FWIW: My son, who is a Yale senior, is not an actor/singer type, and has hung out with friends who were neither athletes or in frats.
One important thing to note about both schools: More than 50% of Dartmouth students are active in greek life, where as the percentage at Yale is about 10%. I imagine that’s because there is just less to do in Hanover than New Haven.