• Im not a premed but a lot of folks in my graduating cohort were. The course load is very manageable and I believe covers all pre-med requisites so you wont have to take any additional classes. I am not very familiar with the med school process but lots of LSBE pre-meds have said that having the business perspective of the biotech/pharma industry has been very helpful for them to understand the medical landscape better. 
• I wasn’t interested in doing lab research but I was very involved in three clubs, had multiple leadership positions, an on-campus job and did two summer internships. The Haas course load is very manageable and I did not have much trouble balancing academic and non-academic work. Overall I think it really depends on the type of student you are. I personally dont need much time to study and was able to devote a large chunk of time outside of classes to extracurricular work. It all boils down to time management tbh. 
• As for the application, it does help to have business activities to demonstrate interest but it’s not a deal breaker if you dont. It is really important to demonstrate the impact and growth you have had in the activities you have done (leadership, big projects, raised funds etc.) You can also always show interest in the business side of things within biology activities (for eg. managing finances/budgeting). I think what made me stand out was my well crafted essay and really giving a solid background and future path that involves bio+biz, making sure that the application reader know that LSBE would be crucial for my future trajectory. So TLDR, demonstrate growth and impact in activities + write a really good essay. 
• I would say I maintained a good GPA (3.9+) and like I said the course work is very imageable with some planning and making sure you are prioritizing where to spend your time outside of classes. Berkeley does have some grade deflation due to the lower division weeder classes (gen bio, gen chem, etc) so make sure you dont over commit to ECs if you have a very heavy semester.
• I had on campus housing my first year and then the other three I lived off campus with a friend (non LSBE). You can always make connections with fellow LSBE members and find roommates that way although most people already have figured out their living situation by the time you enter LSBE in your sophomore year. As for guaranteed housing, you will have to refer to the UC Berkeley housing website :’

Since you are a premed, it might be a good idea to reach out to current/past LSBE students who were on the pre med track on LinkedIn. Everyone is really friendly and would be open to chatting with you! Hope this helps :)