Noob12 Hi there! Great question!
With the "Install available apps" feature, you can install apps that you have installed in your "Owner" profile in other profiles.
If an app requires Sandboxed Google Play, you will need it on that secondary profile as well, as apps cannot communicate across profiles, so Sandboxed Google Play doesn't see the app in the new profile unless you install it there too.
I would recommend first installing Sandboxed Google Play, and then using the "Install available apps" feature to install whatever apps you wanted into the profile that depend on it.
Furthermore, if you update an app in any profile, it will get updated in all profiles.
I hope that answers your questions!