Each applicant's record is evaluated on an individual basis. Both Bachelor of Science and Bachelor of Arts degrees are acceptable for premedical programs. Often a B.S. program in the sciences requires a student to delve into the subject in greater depth, and an admission committee will be aware of this fact. However, an admission committee would expect an applicant to do well with either degree. The B.A. degree requires greater breadth of studies and this, too, may be attractive to all admission committees.
Committees look at the quality of the transcript rather than the name of the degree.
If it interests you, yes. Admission committees look at the level of difficulty of an applicant's course work. Classes are often smaller, and classmates are similarly motivated achievers. Medical schools look for quality in an undergraduate curriculum. A double major or an added minor are only two of many ways to show academic interests and abilities.