i,m pretty sure there is a graduate intake as well... so ur okay. and yes the pays and the benefits get better with time as u get promoted to senior ranks.... the exact pay, i,m not sure,,, but dont even bother converting it to canadian dollars... it would be enough for u to survive, u,ll get free housing n medical etc... things are a lil tough in the beginning, but i never heard anyone dying of hunger, so u should be okay...
the money is crap, but overall, the benfits n lifestyle wise, its still a pretty decent life. as far as the different corps are concerned, i think the top cadets get to choose, others also have a say, but nothings guaranteed... and yes they all go through the same initial training as cadets. the normal standard time was 2.5 years, but i think if you go in through the graduate intake, you might spend lesser time in there... not sure what the pros n cons are for entering as a graduate.
good luck!
if u have the passion, trust me, its a good life....