I have four domains registered and pointed to the same nameservers, and I then have 4 Cpanel accounts (one for each).

I require the four websites to share content and extensions.

I need to build the websites in a test environment as the existing websites are live. I am planning to have

demo.domain1.com (master)
demo.domain2.com (slave)
demo.domain3.com (slave)
demo.domain4.com (slave)

I have listened to the videos and I think my approach is to have separate databases for each website.

I am not sure about the temlate parameters yet, but I will share extensions across the 4 websites, purchase JMS articles and use to share articles. I will use the same theme, but customised separately for each website. I also want to share modules.

My questions in order of importance:
1. If I build all the websites using the subdomains [demo]. How do I then go live? Is it an easy process? with normal Joomla, I simply move the folders but not sure how easy this would be with JMS multisites.

2. How do i ensure that the four websites have their own theme folders that I can customise the look independently?

Your help will be much appreciated.

Thanks

First the concept of Jms Multisites is to share the same Joomla PHP Code.
So you can not create 4 cPanel account because you will have different files and folders owner that will not give you the permission to share the files and folder.

You have to use a single cPanel account and create 4 Addon Domain in this account.
So that all the files and folders will be owned by the same account.

You can effectivelly create different DB for each websites.

1) You have to create the slave site with the target directory. Event if you create temporarly a subdomain for the test.
When you have the domain ready to be live, just add the domain in your cPanel with AddOn Domain to replace the subdomain that you have previously created.

In Jms Multisites, you can create the website with the domain and subdomain.
The switch is done in cPanel to replace the subdomain definition by the addOn Domain that also rebuild a subdomain. Up to you to give the correct "temprary" subdomain name that simulate the future "addOn domain" name.

2) Check with a FTP tool that display the symbolic link to verify if you have a link or a physical directory.
Or use a SSH terminal to display the list of files and folders.
In this case use "ls -l"
to display the "l"inks.

Thanks so much I will do this!!