Correct on the Spartan II's!
Correct on the Spartan III's as well, every candidate survived the augmentation process to become a Spartan. Although some of the augmentations were altered this time round, so over time they'd lose brain function, and they could function even if they went into shock, and a medical injection was introduced regularly to counteract the brain function loss over time (I think).
And they were mass produced as well, with less survival odds, basically used for extreme suicide missions. They used Semi-Powered Infiltration armour, more advanced then ODST armour, but far lass advanced then the MJLONIR armour, it focused on stealth rather then strength, and had special photo-reactive panels that mimicked the environment (camouflage).
I'm not sure about the augmentations and armour use for the Spartan IV's. Apparently (according to Halo wiki) they were Adult volunteers, and surviving members from previous programmes were invited to become a part of the Spartan IV project. They were also augmented to wear a variation of the MJOLNIR Gen2 armour!
Hope that has helped, and like you, if someone reads this and believes I have made a mistake, go ahead and correct me
It does mention Noble team, but it looks as if the game, Halo: Reach, just blows lore right out of the equation :/ Maybe others agree with me, it'll be interesting to see