Hi all, this is my first time posting here, so be gentle.
I just started playing, borrowing some friends armies, and picked up an interest in Daemons for my first army.
Aaaaaanyways, while reading through the Daemon codex I read a piece of lore about a 'caged maiden,' Isha, who's an eldar fertility goddess under lock and key in Nurgle's manse. I liked the fluff and decided that, for my army, I'd twist it to my own dark machinations to use as a theme for my army.

The basic idea is that Tzeentch stole away Isha, who's completely crazy now cause of all the diseases nurgle's pumped into her over the years, and forced her to manifest on an ice world in the Eye of Terror, where all sorts of lesser daemons are manifesting near her because of her aura of chaos.
I'm going to be kitbashing (I think that's the term) the goddess, and then greenstuffing the regular units in the army to make them fit into theme of the army. The tactics for the army will be centering around the goddess's fertility aspects. I have a bunch of units with Boon of Mutation, and the goddess herself is going to be a count as Kugath, so that I can generate as many little guys over the course of the game as possible.
My first question is,
do you think that I could make this sort of army work well enough to compete relatively well against a broad variety of armies? I'm not looking for it to be enormously competitive, I mainly want to have fun playing the strategy, but I do want to win once in a while against you run of the mill army.
My second question is,
what do you think of the army list below? Keeping in mind what I want to do with my army, do you guys believe there's anything better I can do with my units? The Daemon Princes, especially, I'm a little leery over. I definitely want them to have boon of mutation, but I'm not sure if I have them set up the best I could otherwise.
My final question is,
what about the fluff? Do you think its too far off course? Would other players get upset over my army theme, or would they think it was neat? I'm new to the game, so I don't really know enough about the lore and how people view it to make that call.
Full 3000 Point Army List
1 count as Kugath (this will be the goddess)
2 Heralds of Tzeentch, w/ Chariot of Tzeentch, Master of Sorcery, and Boon of Mutation
2 Demon Princes, w/ Ironhide, Soporific Musk, Boon of Mutation, Transfixing Gaze, Aura of Acquiescence, and Mark of Slaanesh
1 Soul Grinder w/ Phlegm Cannon
1 Beasts of Nurgle x7, w/ Noxious Touch
2 Flamers of Tzeentch x4
3 Seekers of Slaanesh, w/ Instrument of Chaos, Chaos Icon, and two will have Transfixing Gaze
2 Daemonettes of Slaanesh x10, w/ Chaos Icon and Instrument of Chaos
4 Plaguebearers of Nurgle x10, w/ Instrument of Chaos
5 Nurgling Models
10 Spawn Models