I know it has been pounded into our heads that bugs/drugs/omm/path are VERY important for the comlex, and recently repro/neuro/psych have also become important.
You should definitely be very familiar with microbiology and the first-line treatments. You should also know second-line or alternate treatments, such as what you can use to treat a chlamydia infection in a pregnant female. I honestly found the micro/pharm pretty straightforward, minus the occasional bug I'd never heard of (but I'm not sure how well you could prepare for this). OMM on my exam was straightforward. Savarese was all you needed, plus a solid background from the first two years. If you studied well for your classes and went through all of Savarese, I think you'll be okay. Pathology is always heavy on both COMLEX and USMLE, and for me, First Aid was generally adequate. I went through Goljan ~2x and I got a few points because of that. But you should definitely be very familiar with pathology. Honestly, I suggest using Robbins a little bit throughout the year (I always give that advice and there are always people who flame me and say it's "way overkill" and unnecessary, but it's the best pathology resource out there). I used it religiously and path was always my best subject.
How is anatomy and the physiology sections of FA factored? (I know anatomy is important for the OMM section, but I'm assuming that anatomy is covered in the saverse book).
The physiology on my exam was a joke. It was nothing like the USMLE. The questions stems were respectable and well-written (the minority on the COMLEX), but the answer choices were all so incredibly obvious. I mean the answer choices weren't even related to eachother. This was only my experience, so take it with a grain of salt. I haven't ever read that the COMLEX has tough physiology and my test was consistent with that. As for anatomy, almost all of my COMLEX anatomy was upper extremity/brachial plexus stuff. A little bit of neuroanatomy that FA covered well. All-in-all, these subjects were straightforward and covered well by FA (although physiology may have required a little bit of outside FA knowledge but a solid background from school would have been adequate). I have heard of people getting lots of lower extremity anatomy with lumbosacral plexus questions, but I had none of these. I also may have had one or two images, but they weren't tough.
Also, does anyone have an opinion on the biochem/embryo/ behavioral science sections?
Biochem on my COMLEX was a joke compared to USMLE, and USMLE biochem was a joke compared to UWorld biochem. COMLEX questions were all straightfoward, with no trickery, and asking simple concepts. I had a few lysosomal storage diseases, but they were all classic presentation and buzzword-laden. I don't know that I had any embryo, aside from maybe a branchial arch question or branchial cleft. I'd say those were the two highest-yield sections from FA embryo on COMLEX. As far as BS, there were a few questions I wasn't prepared for, and they are generally unlike the USMLE BS questions. They wanted me to know concepts that weren't in FA and that I had never seen in class. Definitely know about HMO/PPO and all the convoluted questions they could ask you about that. They didn't really ask me much along the lines of "what would be the best answer to this patient?"