Hey Athithyan,
Visit Kaziranga first and then go ahead to majuli island...
Kaziranga is famous for one horn rhinoceros and there are two ways to spot them in the park. One would be to take an elephant safari early morning at 4.30 and the other would be through a Jeep Safari ... I would suggest you to take how chance with both of them as if you are unlucky in your first attempt to spot wild animals you will for sure spot them in second ...
Majuli being the biggest rivet island in the world.. don't forget to get a splendid sun set view and also the moon rise here... watch a lot of birds those migrate through the island... Don't miss to stay in a bamboo hit on the river shore.... stay in kamalabari for a good stay and access to all places in island ... Lastly if possible see the raas mahotsav which is a must do thing in majuli ...
then go to bondila and Visit bomdila Monastery .. lower gompa bomdila , bomdila view point and other places ....
then go for ziro for a day to visit all the valleys and grasslands ....
after ziro go to Tawang and look out for bhalukpong, sela pass , Tawang Monastery, Tawang war memorial, Tawang war museum....
Hope the information helps you to plan your itinerary ..
Happy Travelling !!!