I dunno, honestly, your Rikki looks much more like the Союзмультфи́льм (Soyuzmultfilm) version than the Abe Levitow (yes, Chuck Jones produced, but Levitow directed and animated) version. Smaller mongooses do look like a cross between a squirrel and a weasel, so it isn't all that off from an actual mongoose.

Kipling didn't understand it but he was a great example of an imprinted animal. He recognized the humans as his family, but that didn't stop him having prey drive or mongoose instincts. And he came in awful handy when venemous snakes moved into the neighborhood.

It actually was Nag and Nagina that were much more hepped up. King Cobras are surprisingly docile in real life - leave them alone, and they leave you alone. They mostly would have minded their own business before Rikki-Tikki-Tavi got involved. He actually broke it in the first place!