This is the most broken part of Pykes kit

if im not mistaken the ability is worded:

ACTIVE: Pyke strikes in an X-shaped area, blinking to champions and executing those below a certain flat amount of health. Enemies in the X that are not executed take damage equal to this amount. When a champion dies in the X, the last ally to assist also gains full kill gold and kill credit, and Pyke can instantly use Death from Below again for a short period of time.

therefore, the last person to hit the target gets double gold, not everyone on the team.

When a champion dies in the X, the last ally to assist also gains full kill gold and kill credit...

It's not team-wide gold share, it's just the last person to Assist Pyke. If you get that last auto-attack in before Pyke mangles someone with Death From Below, you get the shared gold, no-one else.

To my knowledge, this is how gold distribution works:

Kill = 100% Gold Assist = 50% Gold split among all who assisted (so if 2 assists, it's 25% and 25%)

The question I have is how does this affect assist gold?

So in a team fight: Say a kill is worth 100 gold (just for simplicity sake)

Scenario 1: Simple and easy and the way it is distributed normally. Killer = Jinx (100 G) Last Assist = Pyke (25 G) Other assist = Lux (25 G)

Scenario 2: Killer = Pyke (100 G) Last player to assist = Jinx (100g) Other Assist = Lux (?G)

Is Jinx a part of the assist calculation of assist gold split, ie Lux gets 25g, or is it that Lux gets 50G because Pyke's ult passive grants kill credit and full gold to Jinx?

The wording isn't 100% clear but I'm guessing the overall assist gold stays the same and so Lux would get 25 G but I just want to make sure.

they dont get 2x gold on a kill. if pyke kills with his ulti, he gets the gold obviously but the last team mate to assist him gets full gold too.