Lord Ganesha wrote Mahabharata and Ved Vyas dictated it.
Lord Ganesha lost his tusk while writing Mahabharata.
yes
The Mahabarata was written by Ved Vyasa.
Lord Ganesha lost his tusk.
Maharishi Vyas was telling the story and Lord Ganesha was writing it down.
Lord Ganesha broke his own teeth while writing Mahabharata.
The original name of the Mahabharata is Mahabharata.
Yes, Mahabharata is a true story.
There are number of heroic things that Arjuna do in Mahabharata. The list is long and beyond the scope. Better you read the Mahabharata. Rather study the Mahabharata.
the earliest Hindu scriptures were the vedas
Ajaamila is personality who comes in Srimadbhagavata, not in Mahabharata
One highly recommended Mahabharata translation is "The Mahabharata: A Modern Rendering" by Ramesh Menon.