Yes, the damage to the player is inflicted as Battle Damage.
A face-down monster can only be Normal Summoned in face-up ATK position.
A monster can't declare an attack while it is in defence position - unless it specifically says it can (Total Defence Shogun, etc). So your Dragon-type monsters will be unable to attack.If one of your dragons declares an attack, and Dragon Capture Jar is flipped in response, then your Dragon will switch to defence mode and that particular battle step will end without proceeding to the Damage Step.
Yes, if you control a monster in defense mode and it is changed to attack mode during the Battle Phase by a card effect, it can attack. The "Zero Gravity" Trap card is an example of a card that can switch your monsters' battle position during the Battle Phase. But if the monster already attacked that turn, was switched to defense mode, then changed to attack mode again by an effect, it cannot attack again on that same turn.
If your opponent's monster is in attack mode, then the opponent will take battle damage if you destroy the monster with a stronger one. The amount of battle damage they take is equal to the ATK of your attacker, minus the ATK of the defending monster. If your attacker has 2400ATK for example and the defender's is 1800, then the opponent will take (2400-1800) 600 battle damage. If your opponent's monster is in defence position, then the opponent will not take any battle damage at all, regardless of how much higher your monster's ATK is than the defender's DEF.
In Yu-Gi-Oh!, when a Defense Position monster is destroyed, damage calculation does not occur. Instead, the monster is sent to the graveyard without involving damage calculation, as it is not in Attack Position. The player does not take any battle damage from the destruction of a Defense Position monster.
A monster in face-down Attack position is unable to declare attacks. It can be flipped or Flip Summoned, both actions will switch it into face-up Attack position. It can also have its battle position change by the controlling player, switching it from face-down Attack position to face-down Defence position.
If the attacking monster is switched into Defence position, the attack ends. Damage Calculation is not entered, you do not compare the monsters' ATK or DEF.
A face-down monster can only be Normal Summoned in face-up ATK position.
No, if a monster attacks a defense position monster and is then changed to defense position by Kunai with Chain, it cannot be destroyed by battle. In this scenario, the attacking monster is no longer in attack position and thus does not have to compare its attack points to the defense points of the opposing monster. Instead, the battle is resolved in such a way that the attacking monster remains in defense position, and the battle does not result in destruction for either monster.
A monster can't declare an attack while it is in defence position - unless it specifically says it can (Total Defence Shogun, etc). So your Dragon-type monsters will be unable to attack.If one of your dragons declares an attack, and Dragon Capture Jar is flipped in response, then your Dragon will switch to defence mode and that particular battle step will end without proceeding to the Damage Step.
Yes, that is allowed. You cannot, however, attack and then change to defense in the same turn.
Yes. If your monster is in attack position and you attack a monster that has more attack points than yours, your monster is destroyed and you take Battle Damage to your Life Points equal to the difference between your opponent's monster's Attack Points and your monster's Attack Points.
Yes, if you control a monster in defense mode and it is changed to attack mode during the Battle Phase by a card effect, it can attack. The "Zero Gravity" Trap card is an example of a card that can switch your monsters' battle position during the Battle Phase. But if the monster already attacked that turn, was switched to defense mode, then changed to attack mode again by an effect, it cannot attack again on that same turn.
You don't necessarily have to have any monsters in attack position. The monsters you use for the Synchro Summon can be in defence mode, that doesn't matter. What matters is that they are face-up, because you can't use face-down monster for a Synchro Summon.
Only the Spell card Darkness Approaches can flip a monster into face-down Attack position. By discarding two cards, Darkness Approaches lets you flip one face-up monster face-down without changing the battle position (so a monster may end up in face-down Attack position).
Yes. The 'cannot change battle position' limitation is only for manual changes such as flip summons or putting a monster into attack mode. The monster's position can still freely be changed by effects.
If your opponent's monster is in attack mode, then the opponent will take battle damage if you destroy the monster with a stronger one. The amount of battle damage they take is equal to the ATK of your attacker, minus the ATK of the defending monster. If your attacker has 2400ATK for example and the defender's is 1800, then the opponent will take (2400-1800) 600 battle damage. If your opponent's monster is in defence position, then the opponent will not take any battle damage at all, regardless of how much higher your monster's ATK is than the defender's DEF.