That is just weird... How does a lack of calcium and an abscess compare? Did they say she had an abscess in her mouth? If so, is it red/inflamed/tender? Did they not try to aspirate anything if they thought it was an abscess?

What is wrong with people these days...?

One thing I can say is: If they didn't do bloodwork or take radiographs, but said she had a calcium deficiency, then they are trying to suck money out of you...
Also, if the other vet thought she had an abscess, why didn't they aspirate it, do a culture, and see which antibiotics the bacteria was sensitive to? Some antibiotics won't do a thing for some strains of bacteria. If she is on Baytril, that should take care of everything, IF she has an abscess. But if she doesn't, then oh well, and the Baytril will take care of that respiratory infection very well.

Maybe find a different vet And good luck with your baby girl, I hope she gets well.