I think leaving on something that will help mask the other noises is fine. If you family is willing, I would be in the room with the dogs and treats and ask your family members to make the sounds. Since you are expecting the sounds, you should be able to get a treat to Sunshine before she starts to bark. Add a word after she looks to you instead of barking at a sound. That way you can fade out the treats and have a word she knows means she is safe. For example, Gobo was getting a little concerned and surprised by fireworks earlier this month. When he got startled or looked worried, I would say "boom-booms!" in a happy, excited voice and give him a treat. Very shortly I could just say the words and he would happily focus on me. Then I would pet him or toss a toy and he forgot about the startling noise. Next I need to tackle his barking when he hears people talking outside!
First time Chihuahua owner with many years of dog experience!