Hmmm...so letting my imaginations run wild...i have cme to the conclusion that
1) Shyam's illegimate spawn
2) Some cousin's child who they are baby siting
3) Mamaji son (somebody named dhruv) 's child (ok dhruv was a rumour so ...)
4) Arnav's baby (u know in BHPH some kid came claiming he was barun's son...a comedy track maybe)