Considering MCAT preperation, preparation for medical school, how difficult they both are and the job opportunities they would provide if pre-med goes wrong. Any sort of advice is good!
Engineering degrees usually have a lot of sequenced classes and a higher credit requirement than other degrees (for example, 150 instead of 120 credit hours). There’s a reason it often takes engineering majors 5 years to finish college, even without double majoring and/or having a pre-med course of study.
That said, engineering students do go to medical school all the time - so it really just depends on how much time and energy you want to put into college, how long you plan to stay, and how much you and your family can afford in terms of years of college/credit hours.
Engineering often provides more direct career opportunities after college, although that varies a lot depending on the kind of engineering you do (there are likely fewer jobs in biomedical engineering/bioengineering than there are in general mechanical or electrical engineering, for example). But engineering majors can, and do, work outside of engineering or even science at all.
Considering MCAT preparation
Premed reqs tend to provide background material for MCAT. Premed reqs are typically courses open to anyone who has an interest, or is required to take it (eg major req, premed req)., As such premed courses tend to be titled something along the line Bio 1, Chem 1, etc. They tend not to be titled Bio 1 or Chem 1 for MCAT prep. When times comes you’ll either have to obtain study materials and spend 2 perhaps 3 months of dedicated time alone/small group, or take a formalized course (eg Kaplan) to prepare for actual test.
preparation for medical school,
I think doing well in either major would, in part, provide you excellent preparation for skills that would be useful to you as a medical student (eg study skills, time management, exam testing ability etc). As a product of these skills, your hopefully competitive GPAs and MCAT score would help convince med schools you can cut it academically.
how difficult they both are
Hard to say, often how hard something is/is not is in the eyes of the beholder, what profs you get. Only from other postings I’ve read it seems bioengineering is harder/more demanding.
job opportunities
As many who start premed change their minds and of those that applied in last cycle approx. 59% did not get into any med school, it’s good you’re thinking about your major as a Plan B option. I defer to others to comment on job opportunities as to graduating with either major. Good luck.