Hey, I'm a 1st year physio. It's a really interesting course so far but alot of work (you do 7 subjects 1st semester)
1) Chemistry is only necessary for one of the 1st semester subjects "molecules and energy". You can get away with not knowing any chemisty at all but it doen't hurt to know some very basic chem. I did chem until halfway through year 12 and it has helped alot to understand some of the chem concepts in this subject. If your smart enough and willing to work then not doing chemistry in year 12 won't be a big deal
2) 1st year 1st semester subjects are "Functional Anatomy A" (a really interesting subject, deals with bones, muscles, ligamets etc), "Introductory Neuroscience" (very very boring) "Biomechanics A" (physics/3unit maths type stuff, deals with vectors etc), "Motor Performance and Learning" (interesting), "Health Psychology" (interesting, but doesn't have that much relevance to physiotherapy i find), "Molecules and energy" (biochemisty type stuff) and "Designing Health Research" (it speaks for itself)
Hope that helps, if you have any more questions feel free to ask me