If you were using this expression in complete seriousness it would be very blunt and rude, but people would certainly understand what you are trying to say.

Saying "Hi, I'm Sierra. It's nice to meet you." is a common casual greeting. Not many native speakers say "hello" unless it's a pretty formal situation like a job interview or meeting your girlfriend's parents for the first time. In that case you could say "Hello, my name is Sierra..." <- add more information like "thank you very much for inviting me to your home Mr. and Mrs. Johnson"

Sentence A. Your job position is something that you have, it's not WHO you are. You wouldn't say "I am a job." You would say "I have a job."

"Which of the guests are here?" This sentence implies that you already know that multiple guests are here, but you what to know their names. "Which one of the guests is here?" (In spoken english we usually drop the word 'one', but grammatically this is the proper format) This sentence, on the other hand, implies that you know that only one guest is here, but you don't know who it is.

Your "Grandmother's daughters" are your "Aunts"

I would use "burned"