Can someone explain how this interaction works. Does zuckus have to trigger first or can he trigger it after I add the evade ?

Zuckuss triggers first.

It goes thus:

Attacker rolls attack

Defender modifies attack (e.g. Sensor Jammer)

Attacker modifies attack

Defender rolls defend

Attacker modifies defend

Defender modifies defend.

So the majority of additions and modifications are done by the person who just rolled dice AFTER the person who did not.

I like to think of it as the person who rolled the dice themselves gets the last say. So the attacker modifies attack dice last and the defender modifies defense dice last.

I'm guessing you're talking about the Zuckuss Crew card which allows you to take a stress token for each die you force the defender to reroll.

Defender would roll dice, then attacker triggers Zuckuss to force a reroll.

Defender rerolls selected dice and then may modify those dice with a focus or evade token.

You would not be able to reroll any of those dice again with an ability like Lone Wolf.