When wide chest is build as ghost do this in qa single tick:
Revive
Split (keeping the connects)
Damage 1000 each result
Theyll become ghosts WITH connects
Optionally remove ghost timer
Merge when built

Thanks for interesting idea. I don't know if it will be possible to do step 2. I will look through factorio API later.

nope... I've tested - the idea isn't working, because of that connection from a normal entity and a ghost entity isn't visible through any connections API.

So split function that i've tested to work fine on normal entity fails to keep the connection to ghost from chest.

The idea works if entity is placed the last, because this way the ghost is connected to real entity. But this won't work in most cases (when we want the whole blueprint to reappear normally)

Here is the sources of this test version:
https://drive.google.com/file/d/1EXYX2IggcHKJVgwS_O9HQvhWdMSar6wV/view?usp=sharing

It works fine if you put a pole first, and only after that you place a blueprint over it.
However it won't work if you put blueprint on an empty space.
Pity but I can't figure out how to fix this for now...

Also i've fixed a typo in prev file (ModFodler instead of ModFolder in item.lua), so if you already downloaded, please re-download it.

Well, at least I will use your solution to reconnecting circuits when manually merging. There should be some checks to avoid redundant connections. When splitting it would be nice to connect splitted chests together instead of inidiviualy link them to every entity the original chest was connected. But that is doable.

Blueprint placing will have to wait for another solution.