A pair of alpine newts is a solid plan. They are so beautiful. Make sure you keep the water a few inches below the top of the tank and leave some floating cork for them to haul out on. Floating plants also help them hang out near the surface. Mine like to use floating plants as anchors while they rest near the surface. Although they are very aquatic (I've read that some subspecies are more terrestrial, so do your research), I wouldn't keep them in deep water. They like to surface often for air. My female will completely haul out onto a log on occasion.
I keep a trio in a 20 long. I wouldn't keep more than two in a 10 gallon.
Make sure you get a tight-fitting screen lid for your tank. They will crawl out of the smallest hole, even if it APPEARS as if they cannot reach it. They will find a way.
Good luck.