Yes, Flint would be destroyed in that case. You equip Flint to a monster, and if that monster would be destroyed, then you (must) re-equip it to another monster. Though initially you'd probably place it one the opponent's monster, the mandatory re-equip may mean you have to put it on one of your own.
However if the equipped monster is not 'destroyed', ie, if it is tributed, or removed from play by an effect such as Caius the Shadow Monarch, then Flint itself will be destroyed and go to the graveyard.
It mean that to trigger, they had to be sent to the graveyard while they were equipping a monster. That means if they were discarded from hand, or destroyed while face down, or destroyed because the equipped monster was turned face-down or was removed from the field, then they will not get their effect. But if it was equipped to a monster, and an effect destroyed it (or destroyed it and the monster simultaneously) then that effect will be applied.
Flint is sent to the graveyard
Handcuffs Dragon returns to the field in two ways. - If it is not equipped - if it destroyed by battle, it can become an S/T card equipped to the monster it destroyed. - If it is equipped - if the equipped monster is destroyed and Handcuffs Dragon sent to the graveyard, then it can Special Summon itself. So if it is not Equipped, it cannot special summon itself, only come back as an S/T card if destroyed in battle. If it's acting as an Equip card, it can only special summon itself, it can't re-equip itself to something immediately.
Yes, Equip Spell Cards cannot exist on the field without their target. If the target leaves the field, the Equip Spell Card will be destroyed and go to the graveyard.
'Ring of Magnetism' specifically says that it can only be equipped to a monster on your side of the field. If a player takes control of a monster equipped with 'Ring of Magnetism', then the Equip Spell card will be destroyed because it is equipping an illegal target.
then all cards on the field are destroyed unless the union monster has an effect that says that it can be destroyed instead of the equipped monster
It mean that to trigger, they had to be sent to the graveyard while they were equipping a monster. That means if they were discarded from hand, or destroyed while face down, or destroyed because the equipped monster was turned face-down or was removed from the field, then they will not get their effect. But if it was equipped to a monster, and an effect destroyed it (or destroyed it and the monster simultaneously) then that effect will be applied.
Flint is sent to the graveyard
Relinquished's equipped monster is destroyed if Relinquished's ATK is lower than the foe's attacking monster's ATK. If Relinquished is in Defense position, its equipped monster is destroyed if its DEF is less than the attacking monster's ATK. Either way, Relinquished remains on the field.
"Shocktopus" goes into your Spell/Trap card zone and is considered equipped to opponent's monster.
Handcuffs Dragon returns to the field in two ways. - If it is not equipped - if it destroyed by battle, it can become an S/T card equipped to the monster it destroyed. - If it is equipped - if the equipped monster is destroyed and Handcuffs Dragon sent to the graveyard, then it can Special Summon itself. So if it is not Equipped, it cannot special summon itself, only come back as an S/T card if destroyed in battle. If it's acting as an Equip card, it can only special summon itself, it can't re-equip itself to something immediately.
Yes, Equip Spell Cards cannot exist on the field without their target. If the target leaves the field, the Equip Spell Card will be destroyed and go to the graveyard.
Unless the monster specifically says otherwise, it takes two tributes for a monster of Lv7+
The Equip Spell card is called "Ekibyo Drakmord".
'Ring of Magnetism' specifically says that it can only be equipped to a monster on your side of the field. If a player takes control of a monster equipped with 'Ring of Magnetism', then the Equip Spell card will be destroyed because it is equipping an illegal target.
The monster who battles with the monster equipped with Rainbow Veil, has its effect negated. So if a monster equipped with Rainbow Veil battles a Spirit Reaper, Spirit Reaper's continuous effect will be negated, it can be destroyed by battle.
No, there is no synergy. Spiritual Fire Art - Kurenai tributes a monster as a cost. Tributed monsters do not count as being 'destroyed', effects that trigger from monster destruction will not activate when a monster is tributed. In the case of Kickfire, you would not be able to place a counter on it, as the FIRE monster was not destroyed.