All entering freshmen are admitted to the university as a whole, regardless of intended major. You need to meet the requirements for a major to be in it- not critical until you decide to graduate in a few years. Most students are in L&S at UW (no M), especially freshmen. Stating a major for admissions is useful in assigning SOAR advisors, it has no influence on getting in.
Foreign language years in HS equate to semesters in college. If you do not plan to continue in the language at UW there is no reason to take the placement test. Students who complete the semester of the language level they place into at UW can get retroactive credits for HS work. Not worth it for most as you can use the time to take other classes instead first semester. BA needs 4 semesters (years) of one language or 3 of one plus 2 of a second language for graduation- L&S. BS needs 3 of one. Many/most will have completed the foreign language requirement with HS work. btw- you can get a BA or a BS in most majors (L&S)- slightly different breadth requirements. Your major does not determine BA/BS- your breadth reqs do (and you can choose if you meet both).