Miker, this is really basic stuff, and perhaps you might want to do a little more work on your own before coming here with what is a request for education on stuff that is:
1. pretty easy to find out
2. at a
very basic level of science - ie stuff you should have learned in grade school.
NO, using their own reverse thrust is of course NOT the only way to wash off speed. You *really* need to learn about how orbits and trajectories work.
However, yes, they turned the craft around to use reverse thrust to assist in the slowdowns.
NO, they would not have traveled through any significant part of the 'exhaust'.
NO, the temperature of a particle of exhaust at the moment it burns has virtually NOTHING to do with the infinitesimally tiny amount of residual
heat (hint - temperature and heat are two different things) that might be transferred some time later (after the particle had radiated heat out into cold empty space), and *if* any of the particles hit anything 'delicate'.
Given they are being sprayed BACKWARDS into a vacuum with a velocity added to that of the spacecraft, why would any of them get overtaken by the spacecraft???Seriously mate - THINK about this stuff. They are in SPACE, not here on earth, so things are different...
May I suggest you visit Bob Braeunig's excellent site:
http://www.braeunig.us/space/index.htmand follow the links to the ones about orbital mechanics, Apollo trajectories, etc
Also, do some Wiki-ing before posting more of these requests.. and maybe have a good long look here:
http://jean-fred.com/apollo/poster_high_nasa_apollo.jpg (Warning, this is a BIG image!!)
at a schematic of how Apollo worked. This was done a few years before the actual mission, but it's close enough...