The Valentini should be fine in a 30. But the starfish is toast.
Valentini is THE most curious and annoying fish (to tankmates) on the planet. I've had four, one picked on a small eel and lost, one picked on a weakened dogface puffer and lost, one got really BIG and I gave it to a friend for his 110, and I still have one in a 90.
They are curious about everything that enters the tank. Be careful taking water samples, they will bite your fingers. Anything, and I mean ANYTHING you drop in the tank gets immediately "investigated" (pecked), no matter the size.
I love them, you just have to understand they are the nosey old lady nextdoor of fish.