....obviously "choice spirits" is defined by mormons to point out the superiority of mormonism over all Christian religions and the "speshulness" of its members.
I read a book by a former Lds "prophet" (Joseph Fielding Smith, Jr., Religious Truths Defined ... 1959). On page 79, he claims that "pre-mortal spirits are graded."
Hence Mormon leaders try to convey that...
...some pre-existence existed (tho we can't remember it);
...some such spirits there were more "valiant" than others;
...these spirits were "graded";
...and then you get heads of Mormon women's auxiliaries (Mrs. Neill Marriott) -- promoted by the very top etchelon of SLC via its worldwide June 23 broadcast...that "choice" spirits existed in this pre-existence...
...and, of course, these best spirits "landed" in Mormondom on earth.
It's a "neat circle" they've invented that reinforces itself.
It conveys: "Hey, we're great because some spirits were greater in the pre-existence. And the Mormon god of the Church of Mormon picked out those greater spirits to be in Mormon families. And that's just the way it is. (Even tho we can't remember ANY of it)"
Mormon elitism at its finest!