If Zero Point Inflection is on my board and orianna is my legend, i use her ability to turn it into a unit. I then play Ekko, Ingenious and choose to return the Zero Point Inflection, how does the chain play out? Does Zero Point Inflection return to hand before the effect of giving my opponent a point occurs?

Yes — Zero Point Inflection is back in your hand before anything from it happens; in fact it never triggers at all, so there's no draw, no discard, no kill, and no point for your opponent.

The reason is timing. Ekko's additional cost ("return a friendly unit to its owner's hand") is paid in step 4 of the process of play, so the ZPI unit gear is already in hand by the time Ekko finalizes and resolves. Abilities that trigger on playing a card don't check until the play is completed by the card's resolution (Rule 420.4.a), and ZPI's "When you play a card, draw 2" only functions while ZPI is on the board (Rule 385.2) — a card in your hand doesn't see the play at all. So the whole chain of "draw 2 → discard hand → kill this → opponent scores" never gets created.

Worth knowing for other games: if that draw/kill trigger were already on the chain, bouncing ZPI wouldn't save you — only the "kill this" would fail; you'd still discard your hand and the chosen opponent would still score the point. The Ekko line works precisely because it denies the trigger rather than reacting to it.