Holy guacamole, this is a truly amazing guide with all your details and analysis. You must've put a lot of hard work into this , and I thank you for making this. As Lucina's my tertiary character and I'm not too god with her, your guide may very well be what I need to get my head in the game. Definitely gonna come back later and train while reading this simultaneously.
On the negative side though, I have two personal gripes with your otherwise great guide (which is the only reason I gave 4 stars instead of 5).
1. You said most of this was based on your For Glory experience, didn't you? For Glory mode isn't considered that great for competitive play, since Final Destination and Omega forms are the only stages allowed. In tournaments and some friend matches, some people are gonna use other stages to change strategy and the metagame a bit; some of the stuff in this guide might work differently on said stages. Most competitive players I know agree that Battlefield and Smashville are the most neutral stages instead of FD anyway. FD favors projectile characters like Samus, Little Mac (since he doesn't have to deal with his bad air game as much), and combo ones like Shiek. On other stages some of that may change. Not too big a deal of a gripe, but I thought I'd point it out.
2. For the most part, you've said a lot of stuff that's good about Lucina. What I personally am missing is what's WRONG with her, there's no way this character can be perfect. When providing an outlook on characters in games, some people tend to do nothing but praise the character without considering or mentioning important weaknesses they may have. For most off the guide, I've seen you say far more about Lucy's strengths and hardly any of her downsides. I didn't even see you mention her limited combo options or the fact that she has a lot of landing lag on just about all of her aerials. In response to your advice on shorthopping Fairs, I've heard other people say that it's very unsafe and you'd get punished for it, and its better to do a Fullhop Double Fair instead of a shorthop Fair. Other people have also said that her throws aren't particularly great and her recovery is a mediocre (and really dangerous if you don't recover low)
I could be wrong on most of what I just said, but that's what I heard and in my personal experience, they seem to have a point. Still, it'd be helpful to know the downsides of a character inside a guide, so it lets the readers know what they are getting themselves into, the hardships they'll have to deal with, and if the character is even for them.
Other than this though, great guide! Can't wait to see ya update it.
As for the recent Tier lists, I do not pay too much attention to them, but I assume it varies by the way a player is played and who is playing them. The most important thing for you to do is just play at your best against every other character and not worry about whether your character is "naturally good" or "naturally bad" :)