Can Apps be installed remotely?
No. you need access to target device to install the app and register by specifying email id and pin.
How to uninstall App with Device Administrator Privilage?
This is the most common question. TrackMyPhone cannot be uninstalled from Google Play directly. TrackMyPhone requires device administrator permission to monitor your unlock attempts or to change your pin. Hence you need to activate 'Device Administrator' during setup. Android does not allow application to be uninstalled if it has device administrator enabled. So first you need to disable device administrator privilege given to it.
To do that you have to go to Settings -> Security -> Device Administrator. Uncheck application you want to uninstall and confirm. In some older version of android Device Administrator may be inside 'Applications' tab.
After that you can uninstall the app as usual (not from Google Play though). Go to Settings -> Application -> Scroll down to the app and uninstall.
Mails sent by our server lands in SPAM folder?
Open the mail and click on 'Not Spam'. From next time it will come to your inbox. Or else add the email id to your contacts.