Cards with "Alien" in their card name deal with A-Counters. There is no such thing as an "A-Counter monster".
Chat with our AI personalities
Assuming the defending monster is also in attack position, both monsters will be destroyed.
Five-Headed Dragon.
Yes, as long as the spell card is a Quickplay Spell, and the trap card is not a Counter Trap. So you cannot chain Monster Reborn to any trap. Nor can you chain Book of Moon to a Counter Trap, for example.
Unless the monster specifically says otherwise, it takes two tributes for a monster of Lv7+
yes its name is dark blade