This seem like more like a hue configuration question than Ambari, so I moved it to the hue forum.
1. Yes, you can enable webhdfs by checking the tickbox in Ambari.
2. You only need to add hadoop.proxyuser.hue.groups/hosts to the HDFS Custom Config from Ambari.
3. For http_host, it’s recommend to set it to 0.0.0.0, so hue service will listen on all ip address/NIC, but you must put the ip instead of hostname.
Hope this helps.