Dark Fog is useless beyond comparison, so is WDB. DF does nothing, even if it hits. Poison is not worth an attunement slotm especially if you can poison and toxic others with items. Just throw some
at them if you want to see their HP gradually dissapear, or just pressure them.
WDB is very slow, especially with low Dex, to cast and it's extremely easy to avoid. It's a killed spell in very small spaces, where you can't avoid it, but no sane person will fight a caster there. Not to mention DB doing much better job in this scenario.
I'd switch them for Pursuers. Many players have no idea how to fight them, so it will make your life easier. Or you can just use them to make people back away from you and let you cast something else, or heal.
GC is useless if you have Dark Bead, especially with low Dex, you would do better to pack another DB instead. DB can one shot most players if used properly.
I don't understand why this build uses a bow, while it has no need for ranged attacks since it has CSS and can have more ranged spells, while your Pyro and Faith have no means of ranged attack at all.
Might you consider investing 2 points in Str for MLGS. That sword is the best thing an Int build can have to melee. It's used a LOT, so you will have to get real good with it to beat skilled players, but it will be much better than Scythe, as you should keep distance to cast magic, whilst Scythe is all about running at your opponent.
You can use PW and Bellowing for more damage. PW with your Vit should be no issue and you don't really need 56 Poise. You should either go low, or very high Poise, depending if you want to be nimble caster, or tank caster, but the middle way just hinders your options. While the idea of being able to go melee efficiently is nice, without stats to back it up and perhaps some buffs since it's an Int, it would be useless and Quality builds will outdamage you.
There's also no need to go 50 Int if you don't use TCC and Bellowing for max Magic damage. 45 Would be more than enough for this build.