When I applied for 2016 entrance, I only had one of the three for the same reasons as you. (Why spend extra money if it's not needed for many other schools, right?) I ended up getting accepted, but before finalizing the acceptance, I spoke with the admissions office (multiple times to be sure) to confirm that as long as I took the behavioral prereqs before med school started, then I'd be okay. They agreed each time. I ended up taking two
online classes at a
community college, which they also said was okay, and I finished up just a couple weeks ago. If accepted you will have to send all your final transcripts directly to UIC anyway (regardless of what was sent to AMCAS) so the school can verify your prereqs, grades, etc. They also said that as long as you get a C or above in those final classes, you'll be fine.
So to summarize:
- I don't think it matters too much if you have all the behavioral science prereqs done when applying.
- You might want to take the classes earlier in the summer preceding med school in case there's a delay in sending your transcripts (e.g. profs enter in grades late, some schools might send transcripts by postal mail only, etc.)
- Online and community college classes are okay as long as the school is accredited.
- A grade of C is fine if you're already accepted and need to take the classes during the summer before med school. (But in all honesty, who wants a C? 🙂)
- You might want to double-check everything I said with UIC admissions. They aren't very responsive with e-mail, so calling is your best bet.