Adam has 1 instant in his graveyard and casts Talent of the Telepath.
He finds and casts Kytheon's Tactics out of Noah's library.

Is the Talent of the Telepath in Adam's graveyard when Kytheon's Tactics resolves thus giving him the the Spell mastery effect from the Kytheon's Tactics?

Yes. (Assuming no player interferes.)

Talent of the Telepath causes Adam to cast Kytheon's Tactics during its resolution, but it doesn't say anything about causing that spell to resolve. So it doesn't.

Kytheon's Tactics can only resolve the same way any other spell or ability on the stack can resolve–by both players passing priority with it as the top object on the stack. And that will only happen after Talent of the Telepath has finished resolving and gone to the graveyard.