First, why didn't atc tell me to descent?
I have no idea without seeing a log for the flight. Please email the debug monitor log file from your PFE\Logs folder. If you've completed another flight since this issue please send the OLD log. If you've completed more than the one flight since this issue then logs will have been overwritten so please send a log the next time the problem occurs
I waited till I was about 10 nm AFTER my predicted T/D on my fmc
PFE doesn't care what your FMC predicts
Second, does descending without permission void your right t contacting approach?
Yes
Third, how do you configure sids and stars?
What part of this don't you understand when you say the tutorial is no good?
Fourth, is there a way to make PFE atc use the same callsign that FSX atc is using to talk to AI?
No and you shouldn't be listening to FS ATC together with PFE