Let me explain the Lightning meme for you:
It's when the company/creator pushes this particular character so hard and rarely half of the fanbase likes that particular character
Lightning fits that role considering Toriyama (no, not that one) pushed her massively hard for her and Square shoved her in multiple titles and advertising and over favorable FF characters over her.
It's the same thought process for Rosalina considering people believe she's hogging the spotlight from Waluigi, Daisy and even Peach in certain cases when she's popular, Lucario in that light for Game Freak considering he was pushed hard for and he was considering hogging the spotlight (especially when he was Brawl and Mewtwo wasn't) and Lucina lastly due to the base breaker of FEA and people stupidly thought that she'll replace Marth as the face of FE when that's impossible and stupid to consider that.
Don't try to change it up or say I don't understand m, THIS IS WHAT THE LIGHTNING MEME IS:
This character is too popular and might attract the wrong people unlike my character
That isn't what the Lightning meme is, it's just when a character is forced down our throats despite lukewarm reception, nothing more.
Lightning has never appeared "over a favourable character", every game she has appeared in outside of the FFXIII series, has been a general FF crossover, like Dissidia. It's foolish to say she's being forced by appearing in games like this, since she is the main representative of FFXIII, so if they want to represent that game, they jump to her because she is the most well known character from the game, and has also proven to be popular in various polls and just the fact she was a legit role model in Japan (i.e. Japanese people looked up to her as a symbol of what they should be like). It's no different to how Cloud is the main representative of FFVII.
So the Lighting meme doesn't apply to Lightning herself.
Trying to say Lightning is forced by Toriyama is no different to saying Rosalina is forced by Koizumi. Neither are true and there were legitimate reasons for them appearing in more stuff.