Vajji was a mahajanapada towards the north of Ganga in the division of Tirhut. It was a confederacy of eight or nine clans. The capital of Vajji mahajanapada was situated at Vaishali.
First statement is incorrect because though the traces of Pallava and Chalukya temple architecture are available, but its construction is generally attributed to the 8th century Rashtrakuta dynasty. The second statement is also incorrect because the temple is a complete dravida building
According to the Chera poets, Senguttuvan was their greatest king. He is also known as the Red or Good Chera. He led many successful military expeditions. He has also been mentioned in the post-Sangam text, Silappadikaram.