These catfish sound awesome!
At this point, due to the slightly restricted space, I'm caught between these guys and some ottos. I'll probably go with the ottos, just because they're a particularly interesting species to me.
There are a couple issues with otos. First, you should have some natural algae that they can eat immediately. By natural algae, I mean common green algae or the brown diatoms. "Problem" algae like beard, brush, hair will not be touched. Sometimes a few dried leaves can tide them over; oak, maple, beech are safe, pick them up off the ground (in a safe location) and rinse them off.
The reason algae is essential is because otos will be wild caught, and they are almost starved by the time they reach the store. Many die between capture and sale. By having available algae they may manage to settle in; without it they usually die. Eventually they will become used to sinking foods like algae or kelp-based disks. But initially, being wild caught, they almost always ignore these to the point of starvation.
If you do acquire otos, make sure they are eating; they should look full, no sunken bellies. If the store has managed to get them eating prepared foods like the sinking disks, fine, but carefully examine the fish in the tank. Otos that have been in the store for several weeks and are still alive and look healthy are probably going to make it to your tank, but any new arrivals is a real uncertainty.
Otos are not substrate fish, spending their time browsing surfaces of leaves, wood, sometimes the substrate. This is a small tank with the 8 tetras, and the more substrate-dwelling catfish would probably work better.