Can someone please tell me where to find Eidolon specials? More detail inside.

[Senko]

So I'm trying to create three effects for an Eidolon that differ to a normal one.

1) Make it able to take mythic paths.
2) Make it have its own item slots rather sharing them with the summoner.
3) Make it get ability increases at lvl 10 and 18.

The last two are from a custom 3rd party archetype I'm trying to make, most of the archetype I've gotten working but I'm stuck on the last of it. I've managed to find an Eidolon in the companion type and companion type helper tabs. As well as some specific information elsewhere for evolutions or types however there's nothing in there that seems to deal with what I need.

For item (2) there's a basic restriction on Eidolon I presumably need to remove but the Eidolon companion type has no information on this at all but the summoner class refers to a chelpsum in minon restrictions which is where I think I'd find it. So does anyone know where to locate this particular reference so I can modify it?

For (3) I don't want all Eidolon's to have the stat increases just those this archetype applies too. Now in class special I can add stat increases but they take place straight away. Is there a way I can assign that ability to occur at a specific level or do I have to delve into coding to get that?

For (1) I am 90% sure it'll take coding to give the Eidolon mythic instead of the caster but I'll look into that after work if no one knows how to handle that but I figured I'd throw it in here.