That is a lot of faults. There must be some common fault that is confusing the computer. I have read two things about these transmissions that may be of help:
1) The most common failure after a few years is the thermistor. When it fails, it reports that the transmission is cold all the time, which confuses the computer. A shop-quality scanner will read the temperature directly from the computer, so you can see if it appears to be accurate.
2) The transmission computer is very sensitive to voltage variations, so it may start kicking out error codes as your battery or voltage regulator reach the end of their service lives.
3) Yours is the GM transmission, correct? I read that they can loose the pressure modulator that feeds reverse, but your problem does not sound like that.
The good news is that none of these common problems are serious or terribly expensive to correct.