So I managed to finish up my death knight earlier this week. I did most of the leveling experience with him as frost, but ended up switching to blood at the end just for the ease of taking down some of the higher level mobs and large packs of mobs. I'm thinking staying blood may be the best bet for doing world quests as well since I'm not likely to do much raiding on my death knight this time around. I think that activity is likely going to be limited to my warlock and hunter, at least for now.
Overall, the leveling time for the death knight wasn't wildly different than it was for my warlock, finishing up at 23 hours and 24 minutes (or only about an hour and 45 minutes faster than the lock). Of course, the warlock with pet is an absolute leveling machine with no downtime, so that certainly comes into play.
I'll be starting the hunter next while continuing to work on world quests on both the warlock and death knight and also trying to finish up the Suramar quest line on Joar in order to get the Pathfinder achievement under way. There's one piece of the Good Suramaritan achievement that you need for Loremaster of Legion that can't be done without normal raiding until Xavius unlocks on LFR, but I'm not necessarily having the rep to unlock that piece anyway, so not a big worry at this point.
The hunter is up next. I've started him as Marksmanship, but I haven't really been enjoying it all that much, so I'm thinking of switching to Beast Mastery, at least for now. After the hunter, the paladin will be up next as I continue to rotate between melee and ranged. It works out well that I have exactly six of each, at least on the Horde side.
Oh, and -10 points to me for using "at least for now" way too many times in this blog post. I clearly need to cut back on that phrase, at least for now.