Dragonkin generally benefit from power. I feel that 280 speed would be considered the threshold, with anything [over] 280 being fast. So the P/S Infinite Whelpling's 273 speed won't benefit it much. I would go for a P/P.
(The only Dragonkin that is fast enough for speed to matter are the Dragonhawks.)
Just for the sake of comparison. With the Scourged Whelpling on the other hand it's really a tough call. If you make the P/P your main scourged you won't be disappointed with the BIG HITS. The difference in the Health breed is that the health-pool is almost double. So you will be able to survive nearly twice as many hits. They almost even out in the case of this pet. So in that case it's a personal call. Though the H/H may be better against certain elementals.
As far as add-ons go...
" is great. You can put together as many teams as you want. I have a team for each tamer from the two in Kilmador and Eastern Kingdoms that award Sack of Helpful Supplies, all the way up to Pandaria. I have a few Capture teams I go to when I need to capture a pet. And I have a few PVP teams at the ready.
Another good one is "Pokemon Trainer
." Being able to see the enemy's ability cool-downs is a major advantage in both PVP an PVE.
For collecting pets, "PetTracker
" is indispensable. If you've ever used the wowhead maps that show you where all wild pets are on a map, this add-on puts that right on your in-game world-map. You can configure it to show all pets in the zone, pets missing from your journal, and pets that need to be upgraded—or you can turn the add-on off altogether.