Can anyone here instruct me way to install and configure Multi PhP with one apache instance on CentOS 7, and the proper way to test it..
It looks like what you are trying to do is similar to this:
running-two-php-versions-on-the-same-server
I personally would not want to attempt two php version on the same apache instance... I would install different version of php by tarball and run them on separate instance of apache that is also installed by tarball and point each httpd.conf to the different version of php.