Post making contest 2.0

Just for everyone's benefit, here are some rule facts, as I currently understand them. When I say "word" I mean a string of letters, delimited by spaces or linebreaks. When I say "sentence," I mean a collection of words terminated by a ., !, ?, and possibly linebreak.

1. All words must be from some list of (English?) words. "Killer" is in the list, which is somehow surprising. Possibly all the words from a particular book or other written work?
2. Something judged on a per-word basis. The letters b c f h i k o n p s u v w y pass when on their own. Any word that passes can have any of those letters replaced with any of the other of those letters and still pass.
3. The first sentence of the post must start with words of lengths 3, 1, 4, 1, and 5 in that order, though if the sentence is shorter than five words the sequence can be truncated to the length of the sentence and still pass. Adding too many other words afterwards may break compliance somehow.
4. Most likely something to do with Scrabble scoring. Out of all the individual letters, q and z are the highest scoring in scrabble at 10 points each. Q and z are the only letters to pass rule 4 when posted on their own. On the other hand (related), they are the two least-frequently-used letters in English. That may also be relevant.
5. The number of unique letters that are used an odd number of times in the post must be exactly 13.

Edit: Well shit, "yak" not passing rule 2 while "can" does destroys what little I thought I knew about rule 2.