1. WP Super Chace is not mandatory for JNews, but we recommend to use this plugin. You can use another cache plugin that fit with your own need.
2. To translate “best price” word you can translate them using JNews Frontend Translation. You just need to install and activate JNews Frontend Translation plugin. Please check our documentation here for more detail http://support.jegtheme.com/documentation/frontend-translation/
3. For inserting the password when registering process, unfortunately, we don’t have this option at the moment. You may need to do some changes to achieve that.