For Khymera, someone on here converted a lion-like model to accompany their Vect, and they said it was meant to rep a psychic creature that accompanies Farseers into battle. I know that is little enough to go on, as I can't remember who it was or the name of the creature. They used a pretty decent-looking lion model that I had assumed was from the High Elf line (I know little and less about fantasy), but now that I'm looking, I can only find these lions, and they might be too big:
http://www.games-workshop.com/gws/catalog/productDetail.jsp?catId=cat440062a&prodId=prod790879
In fact, it may have been a sabretusk, but I can't believe it as the Sabretusks are some of the singularly most hideous models GW has ever produced!
Also, you could consider the older plastic cold ones (the thick-looking, low-slung ones).
I would vote for DarkMark's suggestion of Pink Horrors, and I would suggest to go further and GS over the eyes, as forum-member Hydra did so well:
For Razorwings, if they don't have to be flying, I'd use Tyranid Rippers. If they have to be flying, consider FW winged rippers.
And what about a Thundertusk/Stonehorn as a big, beastly Talos stand-in?