The best way to get a scourged whelpling is to go to a server that has NOT been included in the CRZ madness.
(Yes, they do exist!)
Folks with EU subscriptions: Earthen Ring - EU
Folks with US/Oceanic subscriptions: The Venture Co - US
I can't speak for Earthen Ring, as I don't have an EU sub, but on TVC all of the heavily-camped pets are plentiful and usually there's no one around to bother you, even though it's an RP-PVP server.
For instance, day before yesterday there were 17 infinite whelplings outside of the entrance to COT.
Each morning there are at least a dozen scourged whelplings that spawn in Icecrown. (Which will change after tomorrow's maintenance, it will become early afternoon rather than morning.)
There are so many fel flames in Shadowmoon Valley that they are, literally, not able to be counted. Defeat one and another instantly spawns somewhere else. The place is crawling with them.
Roll yourself a DK and you can instantly (once you're out of the starting zone) fill out at least 90% of the heavily-camped pets you're missing on your list.
For the ones in Northrend, you'll need to level up a bit - which isn't hard. Just go straight to Outlands and start questing while queueing up for dungeons.
A level 73 frost DK can easily defeat the lvl 80 mobs that hang around Sindragosa's Fall.
I would suggest rolling an Alliance DK, simply to make getting the Cogblade raptor easier. You can fly right into Toshley's station and start battling them. There's nothing that's horde-specific or even easier for horde to get, so come to the Alliance side.
Now, please, if you come to TVC... don't start being an ass and PVPing people just because you can. There are plenty of pets to go around. The atmosphere there currently is "if he's not bothering me, there's no need for me to bother him", and we'd like to keep it that way.... but for pet collectors, this server is simply *amazing*.
(Remember that you don't have to transfer a toon. You can simply roll a new toon on that server, catch the pets you want, then hop back over to your main's server and use those pets.)
