a) I can't. I have no data. If there's more than one, and they were in close proximity, then (say there were two...) they'd orbit each other faster and faster, getting closer, creating gravity waves that were carried off into space. The energy creating the gravity waves was taken from their momentum, and their orbits about each other eventually decayed until their event horizons touched - creating a single, massive black hole nearly equal to the mass of both put together.
b) Gravity waves are created by mass moving through space. (You create them when you wave your arms.) As the two black holes were swirling around each other, a gravity wave was created by their motion; if you could *see* gravity waves, then, from the top of the two black holes, they'd look like a whirlpool of bent space, radiating outward. The waves traveled away from the flailing black holes at the speed of light, traveling the distance to Earth. However many light years away the black holes are would equal the length in years they've been traveling.
I don't know how to calculate total energy of the wave.
LIGO is the Laser Interferometer Gravitational-Wave Observatory, which is shaped like a very large "L", where two lasers are fired from the intersection of the "L" out to a mirror at the end of each leg. Gravitational waves are thought to temporarily shorten, then lengthen the distance between the mirror and the laser, which is seen as interference in the laser light. The effective change in distance between the laser and the mirror is thought to be less than width of an atomic nucleus.
e) Haven't heard of this term, but we have many kinds of 'telescopes' - some that don't use light or electromagnetic energy at all, in order to observe occurrences in the universe. A standard telescope or a radiotelescope will use electromagnetic energy, and can be positioned on the Earth's surface or in space. A Neutrino detector, on the other hand, can be in deep mines beneath the surface, as neutrinos pass through most matter completely. Gravity waves, likewise, are similar - they can be placed in space, on the Earth's surface, or below, as the wave will affect space itself; it's not the wave we look for, but rather the *effects* of the wave on matter (and space).