Yes, but it is mostly used casually. It would be odd to finish an official contract negotiation with "deal".

I think this quote is from "Hype: a Doctor's Guide to Medical Myths" by Doctor Nina Shapiro. It's been over a year since I read it, but I think this chapter was about the dangers of seeking medical advice online.

A woman will often change her last name to her husband's last name after she gets married. This used to be standard, but the practice is becoming a little less common today. Middle names are frequently, though not always, the mother's maiden name (family name before marriage). Also, because middle names are not frequently shared, they tend to be used by people who are very close to the person to give emphasis to emotional statements. Calling someone by all three of their names while saying something affectionate will add an extra level of sweetness to what you are saying. Alternately, when a parent calls their child by all three of their names scolding them, it gives extra weight to the scolding.

"Streamed" is a very commonly used verbal metaphor. It means that so many people passed by, at such a quick pace, that it was as if the people were a stream of water.

Yes, the first two sentences are interchangeable. Fo your last sentence, native English speakers will understand what you mean and will not likely correct you but it's not technically correct. "Fast" is an adjective and you need an adverb here. A technically correct sentence is "The prices rise very quickly." Also, you have two complete sentences here so should use a period to separate them instead of a comma. "The prices rise very quickly. We cannot keep up with inflation."

"By the skin of your/my/their teeth", "giving someone the cold shoulder", and "to cut corners" are all very commonly used. People will often say the first part of "The early bird..." and then let the listener infer the rest. "Birds of a feather", "raining cats and dogs", "elephant in the room", and "you let the cat out of the bag" are no longer commonly used but people will know what you mean if you use them.

In the US, children normally get a standard series of vaccinations every year until they are six years old. This way, then enter school with full immunization. Recently, many parents have been choosing not to vaccinate their children at the usual times. So I believe that the writer is talking about parents who want to wait until their children are older to get vaccinated.