Hi I just bought a seat very similiar to the fidorido from petsmart for $59 it looks almost exactly like that, except on the bottom 2 legs pull out to make it even taller + a food & water bowl attaches to the front + the seat lifts for extra storage, it is the plastic like that & has a fleece mat easy to wash/clean & the seat belt runs thru + a clip to attaches to harness. It is really nice, its not on the website, I had never seen anything like it, I really like. I've had several others & used once/stuck them on ebay. Out of the 2 you asked about I vote the fidorido, but suggest making a trip to petsmart to check out this one it looks like it has more features + cheaper. Good Luck on the seat & congrats on the puppies
Ps to keep pups in a seat it will probably have to be enclosed, so you may just use a larger carrier at first.