Just because Call of the Haunted was selected, does not in any way stop it from being chained.
Greenkappa is unable to destroy a target that has flipped before Greenkappa's effect can resolve, but will still destroy the other one if that remains face down.
If the opponent has no monsters in deck, or no monsters that Last Turn can special summon, then they just don't get a monster, nothing happens in the additional battle phase, and the opponent will probably lose in the end phase.
That would not be legal. Starlight Road has to chain directly to the card it will be countering. That means if you activate a destruction effect and the opponent chains their Starlight Road, you can't use yours.
As per Soul Exchange's effect, one of the monsters for Amazoness Archer's cost can be one of the opponent's monsters.
Nothing really - traps get negated, including Call of the Haunted. Call of the Haunted special summons a monster, and has a condition to destroy itself or the monster, depending on what happens. However it is not true to say it is 'holding' the monster on the field. Simply negating Call of the Haunted will not destroy the monster. While Call of the Haunted is being negated, if the monster is destroyed, Call of the Haunted will remain on the field, uselessly. If Call itself is destroyed, then the monster is not destroyed.
it will not activate. aka will not work.
Assuming that the effect of "The Fabled Unicore" is active (therefore, assuming that you and your opponent have the same number of cards in your hands), both the monster effect that was activated and Doomcaliber Knight will be destroyed.
Call of the Haunted destroys its summoned monster at the same moment it itself is destroyed. In the above case if it's being negated by Royal Decree, then it will not destroy the monster. Even though Royal Decree is being destroyed by the same resolution, it is still negating Call of the Haunted up until the point of its destruction. The end result, Call of the Haunted and Royal Decree will go to the graveyard but the monster summoned by Call of the Haunted will be safe.
A card cannot be activated, if it can't fully resolve. It is usually ok to activate a card legally and have it still resolve as fully as it can if the game state changes before resolution. But for example, you can't activate Creature Swap if one player doesn't have a monster, you can't activate Fissure if the opponent has no monster. Even if all you want is the attack negation part of Super Junion Confrontation, you cannot activate it unless you've got a monster for it to affect. So the situation would be an illegal one, you could not activate it.
If they only control one monster, then it's very easy to work out which monster of theirs has the highest DEF for Heartfelt Appeal to let you take control of.
You can't, it happens automatically
the ghosts will hunt you down then you'll be living in a haunted house...with ghosts doesn't that sound fun
Horrible things... I am haunted by by laptop.