Burrenton forge tender

[undone]

Q: Can I target red cards in the grave yard with BFT ability even if they pose no threat/potential damage.

EDIT: an example is flame kin zealot in dredges GY

[Nihil Credo]

1) BFT doesn't target (which means you can sac him even if there is not a single red object anywhere)

2)
608.7a. (http://www.mtgthesource.com/forums/) If an effect (http://www.yawgatog.com/resources/magic-rules/#effect) requires a player (http://www.yawgatog.com/resources/magic-rules/#player) to choose a source of damage (http://www.yawgatog.com/resources/magic-rules/#source_of_damage), he or she may choose a permanent (http://www.yawgatog.com/resources/magic-rules/#permanent); a spell (http://www.yawgatog.com/resources/magic-rules/#spell) on the stack (http://www.yawgatog.com/resources/magic-rules/#stack) (including a permanent spell (http://www.yawgatog.com/resources/magic-rules/#permanent_spell)); any object (http://www.yawgatog.com/resources/magic-rules/#object) referred to by an object (http://www.yawgatog.com/resources/magic-rules/#object) on the stack (http://www.yawgatog.com/resources/magic-rules/#stack), by a replacement or prevention effect (http://www.yawgatog.com/resources/magic-rules/#prevention_effect) that's waiting to apply, or by a delayed triggered ability (http://www.yawgatog.com/resources/magic-rules/#delayed_triggered_ability) that's waiting to trigger (http://www.yawgatog.com/resources/magic-rules/#trigger) (even if that object (http://www.yawgatog.com/resources/magic-rules/#object) is no longer in the zone (http://www.yawgatog.com/resources/magic-rules/#zone) it used to be in); or, for certain casual variant (http://www.yawgatog.com/resources/magic-rules/#variant) games, a face-up card (http://www.yawgatog.com/resources/magic-rules/#card) in the command (http://www.yawgatog.com/resources/magic-rules/#command) zone (http://www.yawgatog.com/resources/magic-rules/#zone).

109.1. (http://www.mtgthesource.com/forums/) An object (http://www.yawgatog.com/resources/magic-rules/#object) is an ability (http://www.yawgatog.com/resources/magic-rules/#ability) on the stack (http://www.yawgatog.com/resources/magic-rules/#stack), a card (http://www.yawgatog.com/resources/magic-rules/#card), a copy (http://www.yawgatog.com/resources/magic-rules/#copy) of a card (http://www.yawgatog.com/resources/magic-rules/#card), a token (http://www.yawgatog.com/resources/magic-rules/#token), a spell (http://www.yawgatog.com/resources/magic-rules/#spell), or a permanent (http://www.yawgatog.com/resources/magic-rules/#permanent).

A card in a graveyard is not a permanent or a spell on the stack, and the third condition doesn't seem to apply here either (Dread Return does not "refer" to FKZ when it's targeting it. "Referring" here indicates something like Arena's ability.), so no, you can't choose the dead FKZ with your BFT.

3) Even if you could sac BFT to prevent all damage that Dead FKZ would deal to you, upon returning to play FKZ would become an entirely new object and the prevention effect would no longer apply to him.