Are you signing death black Norwegian metal? If so, maybe

I suppose pets get intonation. And if you're looking at them or facing the music stand. Just keep an eye on them and their behaviour. I guess rabbits, dogs etc express how they feel with their body language. If you can read that, you'll know.

When I cook I often sing and dance in the kitchen. This excites one of my dogs and makes her want to play. One of the ways she plays is to kinda run around sideways a bit wiggling her butt a lot while doing a yelpy growl and it's like she is singing and dancing too.

It will likely scare them the first time as it's new/unfamiliar, but they'll begin to normalize it with repeated events (as long as there is no physical/situational aggressiveness toward them). Once they acclimate to the singing, they might still get a small jump scare if you begin abruptly belting out something, but as you continue the song they would likely relax back down recognizing it as not a danger. I find most pets will try to hide/runaway when they don't like a sound, so indifference from a pet is akin to general acceptance of your presence imo.

Here's wishing you a wonderful performance!

My BFF had this skill: whenever they sang an Elvis tune (like "Blue Moon") their cats would start humping. They weren't singing it weird, maybe a little more warbly than normal. Anyway, we were in this zoo once, and I said, "I wonder if that lion would react to your Elvis songs the same way your cats do!" I was just kidding, but my BFF started singing the same way and that lion suddenly became VERY alert and stared right at us. I started wondering if a properly motivated lion could leap that gap that was keeping us separated, and what I would do if it reached us. Anyway, my point is: it depends on how you sing it.

In my experience as a rabbit owner, they will thump at you and run off if you scare them.