Hi, guys, and many thanks for the continued discussion - I am learning a lot, which is always good!
I can't speak for the originator of the thread, but for me, the timing is mostly a result of things getting away from me. I put them in on a Thursday, and intended to bottle them Saturday or Sunday, but it's been ridiculously ridiculous around the house, and I just didn't get it done. Two or so weeks later...here I am....
As for why, my primary reason is to compact the sediment, because I tend to have too much in the bottom of my bottles - not just the usual smudge, but an actual cake of it. Clarity is not a terribly big priority to me, for the same reasons that cavpilot mentioned; this is especially true with these three beers that are currently cold-crashing: two of them are porters and the third is 40% wheat, so I am not concerned about clarity.
If I do decide to add a little yeast, would anyone have any suggestions as to how to go about it? My instinct would be to simply re-hydrate a packet of yeast (it is a generic brewing yeast, about half the size of a Safale packet) in a cup of distilled or spring water and add a spoonful to each batch in the bottling bucket. This should, in my thinking, provide enough yeast to get carbonation going well. If I am wrong, please let me know.
Thanks again, and please keep the replies coming.