I need to repeat my previous post.
COLW is from Aerith's POV and Nojima said while writing On The Way to A Smile, he has to become the character (I guess similar to 1st POV) than letting his own opinion about it (similar to 3rd POV when author is the God who knows everything). So, Nojima never state Cloud & Aerith are lovers. Instead, he wrote Aerith's feelings towards Cloud is "yuujin de ari, koibito de ari". "De ari" mean "as well as" so she treasure friendship and being in love with Cloud equally. A harsh translation would be just "she loves him as well as a friend" but context make it "he's a friend--more than a friend, for she had loved". It fits her personality who treasure every moment, not only treasuring her romantic feelings for Cloud despite unrequited, but also the friendship Cloud gave her since they first met.
Koi (恋) is basically "being in love", people use "suki" when expressing it. It's more selfish, you're the center who desire or want someone to be your lover (koibito) even though that person doesn't feel the same. "Ai" (愛) is the next level, the person you love is the center---an "I love you" in devotion, selfless, giving more than just wanting, only happen when you've been in relationship or marriage, expressing more in "action" than words. Though, "ai" can be used in any kind of love; familial and platonic, even to your pet! Nomura said everyone in the party has love (ai) to Aerith. And "suki" --just like "ai"-- can be romantic or not depends on context. So "suki" is light, while "ai" is deeper or serious,
This is example of using "liking" to express "romantic feelings" from Suzuken and Maaya's conversation in radio show special about Gundam Seed Destiny (2004).
Suzuken: I like your Lunamaria. (Gundam Seed character played by Maaya)
Maaya: I like Shinn (Gundam Seed character played by Suzuken), too. Mmm... actually I like you since we first met.
Suzuken: Whoa....! Like? Like (romantic) love? (Suki? Suki ga koi?)
Because "suki" here can mean "I like your performance" or "I like your character" so Suzuken ask if this "suki" is "koi" type of like. Thanks to that, they were dating afterward, so Zack & Aerith since Advent Children (2005) has been always voiced by real couple hahaha.
So, I dont think it's contradictive or retconning what type of like she has with Cloud because it's already different from Zack.
Because......
Nojima said in CCFF7 Ultimania interview section, that he called Zack & Aerith as "ren'ai". "Ren'ai" is written in kanji "koi + ai" (恋愛) and it means story/poem/genre/song of romance, mutually in love, or in romantic relationship. "Ren'ai" is also used for broad type of romance, from a beginning that is just crush (koi) to unconditional (ai). Though, he also added they're still young, and since he couldn't have much space to build their love story (I guess it's because of PSP UMD limitation that SE rejected the devs' proposal for having two disks), so he made them fall in love at the first sight. By this description, Zack & Aerith is never friends growing up to be lovers, their relationship has always been lovers or first love (初恋) by nature. So, it's still related to Aerith never experiencing a real friendship till she meets Cloud, Tifa, and the others as they set a journey together.
If Zack & Aerith reunited, by nature of their relationship, they're lost lovers finding each others. Rejection would make them over, not turning to platonic friends they never be. I doubt Zack is always by her side because they're
just friends.
EDIT to add this:
Like "Daisuki" is more romantically coded than "Suki desu" for example because you can say the latter to your friend but you'd never say the former to them unless you were straight up confessing romantic feelings.
Zack say "daisuki" to Angeal when he hugged him as Angeal promoted Zack to first Class.
Hamaguchi, perhaps half joking, also say Sephiroth "daisuki" Cloud. (this is in interview video of him answering 50 questions so quick)