I am looking to use one WordPress theme for several sites using WordPress Multisite but want to be able to leave the original theme un-touched, whilst being able to edit the theme differently on each site (the theme being used is very flexible/editable & the various sites are completely un-related and need to look very different).
Having read up a little, if I were to just activate the theme (WPRemix) on several of my sites within the WordPress Multisite system, then any modifications made to the theme would apply to each and every site using this theme. I can see that this fits with the idea of controlling/doing everything once from a single location in WordPress multisite BUT many (including myself) must want to use a theme as a 'template' which you can modify to the needs of websites you create that are completely different/requiring different layouts.
What I want is to be able to use the original theme as a base/starting point for each new site I create within WordPress Multisite and then be able to edit the theme to suit each site's needs without changing the original or other sites version of the theme. Again, from reading up I have come across a couple of thoughts on the matter...
1. Install a new copy of the theme (WPRemix) for each different website you create within WordPress multisite, renaming each copy (e.g. WPRemixSite1, WPRemixSite2, WPRemixSite3), then activate an instance of the theme in each WordPress site (Site1 will use theme WPREmixSite1, Site2 will use WPRemixSite2). A drawback of this approach would be that it kind of goes against the idea of holding everything in one place/only once within WordPress multisite and by having many copies of the theme you are adding bulk to your WordPress installation.
2. Create a Child Theme of the original untouched WPRemix theme for each additional WordPress site you create. I don't know to much about this but believe it could do as per point 1 above without having to install entire multiple copies of the theme, rather just making local changes to the theme and pointing back to the main theme for the bulk of its content. My concern is that you could only use this option to make minor changes (e.g. different background colours, etc) rather than major changes to a theme and its files?
If this IS an option to make major changes to a sites version of a theme then I would really appreciate some help explaining exactly how you go about doing this.
3. Don't use WordPress multisite - stick to having separate single installs of WordPress for each site you create. Very straight forward, in the sense that each install of WordPress has its own version of the theme. Every website you create stands alone with no interference BUT it takes away all the great things about WordPress multisite: a single login for WordPress with access to ALL your websites, a single install of the WordPress files, shared plugins across multiple sites, updates for WordPress & plugins done just once from a single location!
Any thoughts on how best to achieve having multiple WordPress sites using their own independently editable version of the same theme would be much appreciated.