Chastise + Damage reduction?

Is Fanatic immune when using Chastise with a global damage reduction like 'biomemetic plasma vat' or 'heroic interception'?

I would say so - it just says she has to deal herself damage - in the case of stuff like Ra's Solar Flare cards, if he's immune to the damage (via Imbued Fire and Flesh of the Sun God) he gets to keep the Flare in play. Okay so immunities are different…but I think Fanatic would just attempt to hit herself for two points, but it'd be reduced by whatever was reducing it and it'd still count. After all, if she was buffed (eg by Galvanise), she'd deal herself more than two damage - there's nothing that says you have to deal exactly two damage so I reckon if it gets reduced that's still okay :).

Exactly, if she somehow reduces the damage by a total of 2, then that would free her from taking damage. Along with if Ra played Imbued Fire and Flesh of the Sun God and used it's power to make everyone immune to fire, she would attempt to deal herself damage and fail at it!

I think the only way Fanatic would be a bit buggered would be if something had prevented her from dealing damage (eg Ensnaring Brambles or Ethereal Bonds) - in that case she couldn't take the "deal damage" option since she can't deal damage at all, therefore the only option available is to destroy the card.