Is there any new water formed on, or brought to, Earth?
Your explanation(s) sounds correct.

Your first article says as much.


  There is a water cycle on earth that takes wet sediments deep into the
  mantle to be re heated and circulated back up as new sea floor. This
  is where the water in hydrothermal vents originates - it is NOT new
  water. However, there remains a possibility that some of the water
  emerging from the mantle has been there since the formation of the
  earth so some of it MAY be 'new'.


And your 2nd article

This is at least partly semantics calling it "new" water.  When we burn gasoline for example, the hydrocarbon structure becomes Water and CO2 - is that new water, or just re-arranging molecules by chemical reaction and fire?


  I'm also wondering if new water is coming here from
  meteors/meteorites.


Water absolutely reaches the Earth by comets and meteors.   We're hit by comets and meteors all the time and comets especially are water-rich.   That is new water, though I wouldn't want to put an estimate on how much.  Too big a margin of error.

Earth also loses water by UV rays from the sun.   Most of the atmosphere the Earth loses is Hydrogen and most of that Hydrogen comes from Water.   Losing 90 tonnes of Hydrogen per day works out to nearly 800 tons of water per day, which sounds like a lot, but compared to the vastness of our oceans, it's a proverbial drop in the bucket, even over hundreds of millions of years.

So Earth adds water by comets and Earth loses water by photo-disintigration and atmospheric escape.   I've read that it's a net loss, not a net gain, but it's pretty insignificant either way.    Some articles suggest Earth has lost a pretty good share of it's water over billions of years.   I think there's a pretty big margin of error in those estimates, personally. 

In 200 or 300 million years, as the sun grows a little larger and brighter, we might need to begin to worry about Earth losing too much water (maybe).  That's if we're still around, of-course.