My Master CD shipment for Fumika, Kanade, and Nina arrived... looks like I'm back ordered for the other two.
Just listened to Fumika. First off....
I, Nargrakhan, do hereby declare Sagisawa Fumika Mai Waifu. I do not relinquish my claim on Kanzaki Ranko, and call upon the Right of Harem to love both. I henceforth ignore all declarations of others claiming either, and defend exclusive haremship for both. On this day, 4 February 2015, in the Year of Our Lord.
That being said, Fumika's drama track portrays her as boring. You read that right: she's absolutely mundane compared to the other idols. And that is a major source of the charm she excludes.
She's also very talkative and speaks in an intellectual "well read" manner. She's attentive and sharp too, not directly falling for the "trick" Staff-san tries to pull with the ad lib situation.
You read that right:
STAFF-SAN IS BACK!!!

Anyways, her drama track requires the listener to envision Fumika as an incredibly beautiful bookworm with almost zero social experience, who is still a bookworm despite being an idol with a sexy body. She doesn't have any insane moments that make you laugh because of the absurdity of it (like Koume)... or the weird personality of the idol (like Ranko). You'll either like it because you already find Fumika an adorable character; or you'll hate it because nothing about Fumika makes her standout as unique.
***EDIT***Finished listening to Nana. She definitely should appeal to lolicon fans. She's pure youthful innocence... with that weirdly "rude" speaking she has. It features the Producer and Staff-san together to interact with her. She mostly discusses the fun she has being an idol, and mentions her favorite onee-sans like
Kirari and Syoko. She also
gets a little upset and starts crying during the ad lib situation, which should REALLY pull on those lolicon heartstrings.

Her song -- as the demo sample already demonstrates -- is very cutesy. It changes beat during the third quarter of the song, but the first half and last quarter are mostly the same as heard in the demo. Basically stays cute and doesn't stray from that blueprint... no "unique surprises" like Koume and Syoko employed in theirs.