Can newts feel emotions? Are they able to feel happiness, anger, fear or love?
I would say they have some sense of fear, which helps them know to hide and protect themselves from predators, but this could be disputed by claiming this is pure instinct.
The other emotions you describe I very much doubt. They may have feeling comparable with anger based on hormones, which may make them more aggressive etc at certain periods, but that may not necessarily be defined as anger.
It would be nice to assume they have happiness, in order to make us feel better about ourselves and the way we keep them, but in reality it is probably unlikely. However if they could experience happiness, how could we tell?
Love - I think there is no chance of that, like most animals their own survival is too important.
Its feasible that they do possess some kinds of emotion as emotions are a mixture between state of mind and biochemistry, however I don't know whether they would be comparable to our own. Its probably possible to prove that some kind of emotion exists if you have the right equipment, however it would be impossible to specifically say what an emotion is and how it feels to the newt, to me its simply non comparable to our own.