Order of people on a glacier rope team

Having read a couple of books and talked to a few people, below is how I understand the "most important" skills at each position:

Leader:
 - know where to go / stop / turn / belay / etc
 - know how to prusik out of a crevasse
 - set a slow enough pace for the entire team
 - (if ascending) good not-falling skills

Middle:
 - good self-arrest skills
 - good not-falling skills

Last:
 - know crevasse rescue procedures
 - (if desceding) good not-falling skills

1) What did I miss ?
2) How do people prioritize these when some of them conflict ?

There's a bit more to it than that.  Nice if everyone has crevasse rescue ability.  If not, could be quite possible that you want your most experienced at the rear of the rope or your lightest out front.  No steadfast rules of thumb here, although I generally advocate that if you are inexperienced, you should not be on a glacier with solely one other person (i.e. team of 3 or 2 teams of 2 minimum).

Does "know where to go / stop/ turn/ belay etc" translate to "is the most experienced at determining the most likely place(s) for, and can recognize,  covered ( hidden) cravasses" ? because that's probably the most important aspect of leading on a glacier.

Everyone should have good self-arrest skills.

If skills are equal -  lighter climber goes first downhill, since he/she is less likely to break through.  I've always felt that if the descent route is the same as the ascent (i.e. following ascent tracks) the lighter climber can go first, even if he/she has lesser skills at "cravasse finding".

mmmm...Chris posted while I was editing my post.