“locating planets where extrasolar life might survive took a step forward”
No, finding one thing that might support life on a planet where that is missing 8 or 9 other elements needed to support life is not taking a step forward. You’re still in the same spot you always were, where Earth is the only planet in the universe known to be capable of supporting life.
Yep.
The most "Earth-like" planet ever discovered is almost exactly the same size and mass as Earth and orbits a yellow dwarf star at relatively close to the same orbit. It is called "Venus" and up close it is not very Earth-like.
Methane is common throughout the galaxy. So are organic molecules, even complex organic molecules. Making them is easy. Just take oxygen, hydrogen, carbon and a few other elements, contain them in a high-pressure environment with a heat source, and mix them around for a few million years. Gas giants work really well at that.
How to make the jump from the most complex organic molecules to the simplest living organism is the big unknown. Unless and until we either (a) figure out how to make a living organism from scratch in a laboratory, or (b) find life somewhere else, we have no idea how common or rare life is. It is entirely possible that the rest of the universe is completely sterile.