And by precedence of the etiquette rules, the Q and K leave together before you could use the J to pull the K away, correct?
Not quite - the J provides an exception to rule 2. If there is no J of that suit then you are correct - you must discard any K and Q of the same suit. But if (and only if) the J of that suit is also present then you can keep the Q and discard the J and K instead.
This gives an incentive to hold on to a J. But if you end up with more than one then you must discard your whole hand and start over (rule 4) unless you can ditch one with his K first (rule 2). The whole dance between K, Q and J is designed to give a push-your-luck dynamic and hopefully set up some tense decisions...
Cheers, and thanks for your ongoing support of this wee game!