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[Halo Universe] Questions about lore

So, I've not played most of the Halo games, but I do follow the lore to some extent by either watching the cinematic play through/let's plays, or reading the synopsis'. However, I've found a bunch of stuff confusing...

1) The premise of the importance of John 117's existence in the first two Halo games is that he's the only Spartan left. Halo 4 and 5 make it abundantly clear this isn't the case, and there's in fact a bunch of other Spartans around doing other things, such as Blue Team. Is this just an inconsistency or was this ever retconed?

2) In Halo Reach, Cortana is claimed to be a Forerunner AI. In Halo 4, Cortana is claimed to be a human AI who's creation was evolutionarily guaranteed by the Librarian. In some other piece of Halo lore, Cortana is claimed to be simply a psychological graft of Dr.Halsey in AI form, (hence Cortana looking like just a young version of Halsey). What's the deal?

3) Where does the Arbiter get his different armour from in Halo 4/5?

4) Where did the Brutes go?

5) Where did that flying species from the Covenant go after Halo 2? I've never seen them again. 

6) In Halo 3, the Elites leave the covenant and are replaced by the Brutes. Humies and Covies call truce. In Halo 4, when Master Chief is awoken from crysleep, he's attacked by an Elite, and when he asks "I thought we had a truce?", Cortana responds "things change"; what changed...? lol. 

7) If the Covenant worship the Forerunners, why do they fight the Prometheans? 

8) In the Covenant civil war in Halo 2, the hunters side with the Elites; in all subsequent Halo games, the hunters appear to side with Covenant. ??

9) Are Lock's team actual super soldier Spartans, or are they just good soldiers which earned the right to wear Spartan armour? If they aren't genetically and biologically engineered super soldiers, how could Lock ever spare with Master Chief, a Spartan II and not lose immediately?
gpt
1. After the Fall of Reach information in the UNSC was hazy at best and it appeared that the only surviving Spartan-II was John-117 however as time went by it was quickly discovered that other's had survived and in fact one of them was onboard the Pillar of Autumn in a comatose state (Linda). Afterward the Halo event other Spartans were simply assigned to other missions than the Master Chief so it appeared he was alone to the majority of the UNSC.

2. Cortana is the first ever AI made from a human brain, she was not a forerunner AI in Reach she simply studied forerunner objects. 

3. Made it himself probably? It's likely some based on older Sanghelli armor design.

4. Split off into warring tribes, 1 tribe even sought peace.

5. They were in Halo 3 actually, Post-War most returned home whilst others joined various Covenant factions.

6. Some Elites did not like allying with the humans which is what the Arbiter wanted. So they split off and continue war with the UNSC.

7. The godlike image of the forerunners was largely shattered with the revelation that they commited suicide against the Flood and not ascend to "godhood" . But the primary reason the Covenant fight the Prometheans is because the Promethean's turned on them, (hard to worship something when it's shooting at you)

8. The Hunter's that sided with the Elites may have split even more when the Elites themselves fractured into multiple factions, there's large possibility a good number of them joined M'dama and others.

9. Locke and his team are all Spartan IVs and thus have the required enhancements to wear the armor. Spartan IVs have roughly the same physicals as Spartan IIs if they are both in armor which allowed Locke to hold his ground.