It might be better to just say, "Thank you." and omit "in advance." I think this implies that you are grateful that they took their time to consider your request. It would probably be a good idea to thank them again afterward, this time for whatever work they did to help you.
Unfortunately, some people (many of whom are very outspoken) will be offended by almost anything.
Usually, the best practice is to use the conventions that are generally accepted among whichever group of people you are communicating with.
There are no hard and fast rules about what greetings (salutations) to use in email. If you want to be polite and formal in English, then you should say something like:
Dear Mr. Smith:
Dear Ms. Jones:
Dear Dr. Jekyll:
Dear Prof. Einstein:
If you want to be polite and informal, replace the colon (:) with a comma:
Dear Mr. Smith,
etc.
When authors send me a manuscript, regardless what salutation they use to address me, I always start off this way:
Hi, Dr Jiang,
Hi, Prof Jou,
(Almost all my clients are Taiwanese doctors and medical school professors).
When I write to my friends, I always start of the same way:
Hi, Tam,
Hi, Kathy,
This is just a stylistic choice, a personal preference.
For business letters other than my editing, however, I always use the polite formal style in the first examples.
There is no definitive answer to your question, just a recommendation that for serious and important business letters (anything not to a friend or a penpal, and anything not informal), that you use the polite formal or polite informal style. You can find lots of choices in handbooks about how to write letters in English. Be advised, however, that different brands of English prefer different styles. The one that's best is the one you feel most comfortable with and the one that you think works best for any particular letter.
The more formal and more polite your initial salutation, the more emotional distance you put between yourself and the person you're writing to.
For friends and otherwise informal emails, the same rule of thumb applies: The one that's best is the one you feel most comfortable with and the one that you think works best for any particular letter.
Everyone has a different idea about what's good.
Best Answer
If you had a response, then you know the name. You can then reply to the name that was given to you.
Sometimes I am less formal and only reply:
I suggest you pitch your tone from the reply you received, which was
In which case the reply is a simple