will the above settings allow curl other sites with port 80, yum and wget?
Do i need to create new state for every output port?
If you set the output policy to DROP then you need to explicitly allow the ports to which you want to make outbound connections. Other ports opened by the same connection or related to it will be allowed too by virtue of the RELATED,ESTABLISHED rules.
With the rules you have at the moment, you'll be able to connect to other web sites and SMTP servers from this machine. It also allows you to connect to your webmin port on other servers but I suspect you just didn't get around to removing that yet. You're also allowing traffic to your server from others on http[s], SMTP, relocated ssh and Webmin ports. Any traffic related to those connections is also allowed.
Since you started this thread about DNS you will need to allow outbound traffic on destination port 53, both UDP and TCP. Whois traffic is on port 43.