You don’t need to talk about career aspirations or major in your PIQ.
PIQ 1 is leadership
PIQ 2 is creative
PIQ 3 is talent or skill
PIQ 4 is educational opportunity or overcoming a barrier
PIQ 5 is overcoming a challenge
PIQ 6 is academic subject that inspires you
PIQ 7 is community
PIQ 8 is anything else you want to share
With the exception of 6, the PIQ don’t really touch on major or career aspirations.
Looking at OP’s list they could choose to write about
Hospital volunteer, food pantry, soup kitchen or mission in PIQ 7.
Youth City Council, HS event or Link Crew in PIQ 1.
Art commissions/art competitions in PIQ 2
CC intro to psych, sociology, cog sci in PIQ 6
They could choose any on their list and write about PIQ 3.
In the A&A section, I would suggest organizing your A&A by importance to you, and possibly type of experience. That might split up your dental involvement into work experience, other coursework and extra-curricular.
My oldest studied Cog Sci with a neuro emphasis at UC Davis. Several people in that major were pre-med. However, Cog Sci at UCI is in Social Studies. After my student was admitted to UCI, we attended an open house and they made it clear that Cog Sci should not be used as a major for pre-med students. This was several years ago, so @fonechip should research if that is still the case before applying as Cog Sci to UCI.
Finally, UC Davis has a great Health Professions Advising department with a very comprehensive website. I suggest poking around on their dentistry page to see which pre-reqs are required for different dental schools. You’ll want to make sure that you will be able to take those courses (without restriction) with a Cog Sci major at the schools you are applying to.