Best practice for multi site development, staging, etc. [Special snowflake details inside] The story:


Site A is running in Craft 3 as the primary site. (On a subdomain, if that matters.)
Sites B and C are running in ExpressionEngine 2.
I need to write new HTML/CSS for sites B &amp; C.
I need to import and cut/paste content from sites B &amp; C so that eventually, sites A, B &amp; C are all running under the original Site A Craft install.


Meanwhile, content will continue to be updated on Site A.

So...

If I clone Site A and develop with it, on my local PC, importing content from the other two sites, I can get all three sites running together. However, then I'm unsure how to reconcile the data from Site A with my development version.

What do folks recommend?
If I'm understanding correctly, there are two methods I'd suggest;


Instead of reconciling the data from Site A, I would first setup Site A with Site B + C and add any new fields/sections you will need, then set up project config so that any structural changes you make locally on development will be made remotely. Put it live, then you/the client can populate the content on the live Craft install whilst you work on developing the theme locally.
I would look into the Feed Me plugin. On Site A you can set up Element API to expose all your content in JSON, then on you development site use Feed Me to import the content from Site A. This may take some setting up initially depending on the complexity of your site, but once it's done it's just a case of clicking a button to pull the latest content.


Hope that helps!