Yes. It might be possible that there are countless sentient species in the universe, but we do not know for now.
Despite much debate among people and scientist, there is no official proof that there are countless semi-sentient species in the universe.
Though some scientist say there is a possibility that there are countless non-sentient species in the universe, there is no concrete proof right now to be sure.
In my opinion, yes. There are at least 10,000 trillion sentient species (100,000 per galaxy) in the observable universe.
It isn't currently known whether there is even a single species outside Earth - sentient or otherwise. The number you mention has been made up by somebody.
Currently it is not known. Earth is the only known planet to hold life so far. It also depends at what point you consider a living thing to be sentient.
To make 100 billion separate books of all of the information of 10,000 trillion sentient species (100,000 per galaxy) in our universe, you would need to begin by researching each species. Then combine the information using a computer.
No. Sentience is not one dimensional but five: cognitive, recognitive, sensory, inherent, and logical. Each of these has a range value therefore the measure of sentience is n5 variable value.
Yes. There are countless planets in the universe.
Niado Duegad is a fictional species from the Star Wars expanded universe, specifically from the Legends continuity. It is described as a non-sentient reptilian species native to the planet Nizon.
Yes. There are countless planets and moons in the universe.
Yes. There are countless globular clusters in the universe.
Yes. All sentient species do have unusual features. But for now, it is unknown.