Hi, Ved.
Lockout feature is implemented with custom authentication script written in Jython, so whatever functionality is possible to code using Jyhon can be added to it. I can't see any difficulties in using some libraries for REST calls or sending emails from within the script.
Please note though that Community support doesn't cover custom script development, but [there are plenty examples](https://github.com/GluuFederation/oxAuth/tree/master/Server/integrations) of custom scripts you can study.