Fiske is excellent and was the only college guide book my D used. I agree with everything @intparent says, and I do not agree with all that @WWWard says:-) Your sister doesn’t need to apply to any more than 8-10 colleges if she has a balanced list of good bets, match, and reach schools, UNLESS she is looking for as much merit aid as she can get.
More applications from less qualified students, or more sloppy applications, shouldn’t make it harder for anyone to get into college, despite the common app. My kid applied to 12 colleges and got into nine. She didn’t get into two tippy top reaches, and was waitlisted at two mid-low reaches but got off the waitlist at one of them. Her list was balanced, and in fact, she shouldn’t have applied to a few of the colleges she did apply to, because she lost interest in them.
I do agree that Niche is really good for students. My D spent a lot of time there. USNWR, IMO, is not useful for anything at all, unless perhaps the paid service is good. We never used it. Apart from this website, the best website for comprehensive college info about virtually every college is college data. It basically complies all the common data set stats for any college and publishes it so you can get the info in one place. It also has lots of helpful student stories about getting into college and useful articles about college.
Finally, if your sister has just entered high school, I suggest holding off a bit on the college stuff. There is a lot to get used to in ninth grade, and adding the stress of thinking she must do well to get into college might be better left unitl later in the school year, or next school year. I have a sophomore and he is already sick to death of college stuff, just because he had to live through it with his sister. I plan on waiting until next summer to start his college search in earnest. Of course, if she is raring to get started, go for it, but don’t push it.
Ps, yes, Fiske has info about UK and Canadian schools.