AP credits can increase a student’s class standing but not necessarily for course selection and definitely not for housing. Being a recruited athlete, Regent scholars, Honors etc… will get priority registration.
UC Davis and UCLA not longer factor in AP credits for class registration but some UC campuses may still factor them in. Also UCD and UCLA do not accept AP credits for all GE requirements.
Regarding housing, unless the student again is a Recruited Athlete, Regent scholar, Honors scholar etc… AP credits are not factored in at all.
Even some UC Honors programs (UCSB) do not give priority registration for courses.
You need to look up each campuses AP credit policies since it can vary along with the benefits of Honors programs if interested.
http://talk.qa.collegeconfidential.com/t/comparing-uc-honors-programs-and-regents-scholarships/