Yes, you can use the effect to destroy a stronger monster, and then attack a weaker one. You need at least 2 out of 3 heads on the coin flip.
If you are asking if "Five Headed Dragon" can attack the turn that it is Fusion Summoned, then yes, it can attack (unless the card used to summon it has an attack restriction on it). If you are talking about attacking on the very first turn of the duel, then no, "Five Headed Dragon", and any other monster, cannot attack.
Montage Dragon does not have any activated effects so it has nothing that can be chained to. However if Fiendish Chain is used on it, then it will not be able to attack, and its continuous effect that grants it an ATK value will be negated, and it will be treated as 0.
Yes. Most negation effects like Light and Darkness Dragon, and Stardust Dragon, can be used in the Damage Step, which is where Newdoria triggers. Stardust Dragon can indeed be used against Newdoria's activation.
yes star dust dragon can use its effect anytime in the game unless you have used one of your spell or trap cards or effectd
The dragon in "The Lost Hero" is vulnerable to being controlled by a metal charm in the shape of a dragon's claw, which weakens and manipulates it. This charm is used to force the dragon to attack Camp Half-Blood.
Stardust Dragon negates and destroys the card it is used against. Prime Material Dragon can only be used against an effect that destroys a monster on the field. So, if Stardust Dragon is trying to negate a Dark Hole, then Prime Material Dragon cannot be used against it. But if it is trying to destroy a Dark Armed Dragon, then Prime Material Dragon can be used against Stardust Dragon in this case.
they are weak against it ex. ice beam
Majestic Red Dragon cannot use its effect negation effect against Obelisk the Tormentor because it targets. However its destruction effect when it attacks does not target, and can be used against Obelisk.
Tuner's Scheme has a destruction effect, but it does not 'activate'. Stardust Dragon's negation effect can only chain to destruction effects that activate, so it can't be used against the destruction caused by cards like Tuner's Scheme or Call of the Haunted. Stardust Dragon may also not stop Tuner's Scheme's initial resolution. While it does have a destruction effect on one part of the card, Stardust Dragon can also only be used against an effect which will destroy something on resolution.
OBELISK: 4000 Winged dragon of Ra: the combined power of the three monsters you used to summon him. You can increase its attack by paying lifepoints Slifer the sky dragon: 1000 ATK per card in your hand.
Light Pulsar Dragon's effect allows you to Special Summon a Dragon-type monster from your Graveyard when it is Special Summoned. This effect can only be used once per turn. Additionally, if Light Pulsar Dragon is sent from the field to the Graveyard, you can Special Summon a DARK Dragon-type monster from your Graveyard.
Yes. The whole idea behind Proto-Cyber Dragon's name changing effect is to let it be used for Cyber Dragon support and fusion.