Is request feedback limited to people on the platform?
No. Currently you can request feedback from external parties as well as internal. External parties receive an email providing a link to give their feedback. They do not have to install anything.
Can I see the praise or feedback of my users?
It depends. Praise can be seen on company level if this has been set as such by the provider of the praise. Otherwise you can only see the praise and/or feedback of team members of which you are the team lead or coach, and if the visibility level has been set as such. You can find more information about visibility levels here.