For Indian Citizens who are travelling to Nepal passport is not mandatory but instead for that they have to carry following documents:
Yes, Indian currency is accepted in Nepal. While doing shopping you can get Nepalese currency in exchange. However, in Nepal 2000,500,200 rupees notes are not accepted.
Anyone can book the Nepal tour package between October and December.
Yes while booking Nepal tour package keep in mind that Indian Sim work there if you recharge the roaming data facility. So, the best way is to can purchase the local sim card.