And the title track seems to be a sequel to "Naive To Innocence".
I had the same thought... and you are SO RIGHT ON re: 18, nailed it!
I like that she's experimenting with song structure a bit in this album. Besides Cocoon there's a few other tonal shifts in other songs that I'm really digging-- DADAAAN ends up in a completely different place than where it started, and in Lita where she's like "hey, this is boring" and breaks it down is so great. Waiting for You had me smiling the whole time, it's kind of reminds me of "Ai wo Oboeru" in that it's just straight up fun. Also sometimes when she sings in English I feel like she's very careful to enunciate which is something she does not seem to bother too much with in Japanese haha, so it's kind of cool to hear her sing in English in her more normal voice.
Considering how strong the rest of the album is I wonder why she released both Planet and Chouchou Musubi as singles... but I think it just might be me getting a little tired of her doing a lot of very similar sounding ballads, when they work they're great but the majority make me feel like she's kind of writing the same song over and over. Part of the reason I love her so much is how she can be genuinely touching with so little-- the last line of Amaete Yo literally made me tear up-- so the ballads just seem kind of empty in comparison. Obviously a lot of people really love them though so maybe it's just me.