not a thing
Stardust Dragon has a triggered effect that special summons it from the graveyard on the turn that it negated an opponent's effect. Forbidden Graveyard will negate this trigger, Stardust Dragon will not be summoned.
The monster will always return to its owner's Graveyard. Incidentally, if the effect of the destroyed monster activates while it is still on the field, you will be able to use it; however, if the effect activates in the Graveyard, the card's owner will control the effect.
"The Rock Spirit" can only be Special Summoned from the Graveyard, if it was Special Summoned from the Hand via its effect first. In other words, if it was "improperly" sent to the Graveyard, such as by discarding from the Hand, it cannot be Special Summoned from the Graveyard. If it was successfully Special Summoned by its own effect onto the field and is then sent to the Graveyard, it is then elligible to be Special Summoned from the same Graveyard. However, if it's Special Summon was negated by a card effect such as "Solemn Judgment" and sent to the Graveyard, it cannot be Special Summoned from the Graveyard.
No. The effect of any monster face-up on the field is negated once sent to the graveyard, unless the card itself states that the effect still works while in the graveyard
Cyanide
Yes, if a card effect activating from the Graveyard will destroy a monster, Spell, or Trap card "Stardust Dragon" can be activated to negate the effect. Even though "Stardust Dragon" states that it destroys and negates cards, it can still negate an effect resolving in the Graveyard; the card in the Graveyard simply will not/ cannot be destroyed.
As a matter of fact, yes. The end of Anubis does negate Stardust Dragon's effect as long as he is on the field. Since Stardust Dragon's effect activates in the graveyard, and The End of Anubis' effect states "Monster cards that designate a card(s) in the graveyard or activate in the graveyard are negated."
Cyanide
No. The effect of Buster Blader specifically states that "This card gains 500 ATK for each Dragon-Type monster on your opponent's field or in their Graveyard."
Colossal Fighter's effect triggers after he hits the graveyard. That means that he himself is in the graveyard when he activates, and he is a valid target for his own effect. So yes, he may summon himself.
Some chemical weapons as tabun, sarin, soman are considered slow effect agents.
Totem Dragon only has one effect that activates, the one that can special summon itself. If there are other monsters in the graveyard, that are non-Dragon types, then this effect cannot be activated.