I have worked a little escrima after the formal adult class. 1) I am with Exile on this, it absolutlely has to be an upper ranking belt. I am a brown first formally in Judo so I met the requirement. 2) We, the adults, were told that a sword, tonfa, escrima, knife, etc is nothing but and extension of your hand. 3) So the fact the strikes like knife and ridge hand strikes were the optimal.
In hapkido cane is part of the blue belt cirriculum.
Matt
I added numbers to your post to address it. I'm not trying to get off topic here by a debate on which is better etc. etc.
I am glad to see that you are working on the escrima after your adult classes. I am biased in this because I have been really studying more of the FMA in the last 14 years than focusing on TKD studies, but my FMA studies has helped with my knowledge in TKD but in a different way.
1) I believe that the study of weapons and how they relate to empty hand defense is a very important aspect of training and should be included right from the begining. Not so much for kids as for adults though. In order to effectivly defend against a weapon I think you must study and know the weapons characteristics (as in impact, edged, or flexible weapons) and you gain that knowledge through applying techniques to individuals and they in turn applying them to you.
2) You are right we are told that the sword, stick, knife, rope is an extension of the hand, and it is. But the question is how many people are seasoned enough martial artists that really understand this. I mean a pocket stick has the same characteristics as a good ball point pen, or a hair brush, chop sticks, silverware etc. etc. Or your flash light is like a short escrima stick (I like the 5 C cell Mag light my self

), but then so is the tire iron, or that pry bar screw driver, or a raquet ball raquet. But unless people drill it into their minds and I believe actually practice using these items to reinforce the concept into their minds then they don't think about it when the time comes.
3) I believe I understand your intent here with this comment (although at first it threw me). The knife hand strike can also be a spear hand to the eyes (the fingers are formed the same way but the angle an execution of the technique is different), and the ridge hand is like a hook punch.
I've got to run and take my son to school I'll finish in another post.