1.) The loop gain phase for low frequencies (including dc) MUST be -180 deg. due to the neg. feedback case. Otherwise the whole circuit would not work.
2.) I don't understand your question regarding PSRR.
Determination of stability margins require breaking the loop - otherwise you cannot inject a test signal. However, in order to restore the operating point, the dc loop must be maintained. Therefore the large L. But this crude method cannot mirror the load at the breraking point.
Other and more exact methods (Middlebrook et al) can do both:
Maintain dc operating point and no loading errors.
Ken Kundert has written a good paper that describes these methods.
Remark: Sorry, it was F. Wiedmann who has collected something about phase margin:
http://sites.google.com/site/frankwiedmann/loopgain