Aphi Diva... when I have a chance I will PM you...
I must first say... that what constitutes a "TOP" PNM is what your chapter wants in a NM.
IMHO... The answer to your question is, in short... all the above. To expand... a legacy to a competing house is almost as attractive a NM, as your GLO's legacies.
More importantly, there are a few PNMs that every house is interested...
A young lady that is so incredible all around... she is most likely a "Mississippi" legacy (if we are talking Chi O, DDD, DG, KD, and Phi Mu)... has a good GPA; involved in school, church (important), and community activities; and comes from a certain area or high school.... looks... well all Mississippi Girls are beautiful!!
I just cannot imagine that any chapter would not look for these things in a NM. However, I am only speaking from my opinion and knowledge.