The name is great but in Chinese "开" isn't a chinese last name ."谐" is a good word ,and it means "peace"

To choose a last name, you can reference the "Hundred Family Surnames"(百家姓). In the wikipedia, there's an article about that. (http://en.wikipedia.org/wiki/Hundred_Family_Surnames) Or, in another way, translate your name "Kaushik" directly in pronunciation. And if you do that in google translation, it would be "考希克". However, "开谐" is okey if you like it and your country doesn't have any specification when you want to applying official documents. In this website ( http://tw.zhonghuaqiming.com/zidian.aspx ), you can submit each word and find the meanings. For example, "开" means discharge, karat, opening;while"谐" means humorous, in accord, in harmony.

"腾" is very meaningful , many chinese boy called "腾".