Does the second laptop need to run already centos 7?

Technically, your other system doesn't have to run CentOS 7, but your life will be much easier if all your systems are running the same version of the same distribution. Also, you will need to make sure that even if you are running something other than CentOS 7 that you are still using the same versions of all the OpenStack services. I would not recommend trying to run in a mixed environment like this.

That way lies madness. Madness!

Is packstack the recommended way setting up a cloud with redhat? If not what other methods are supported?

Many people install and configure the packages manually, or make direct use of the Puppet modules for OpenStack, or use some other deployment solution. Packstack is probably the simplest way to get things started.