There was recursive blueprints extended out of 0.16

Can you consider adding that functionality? The deployer would check the area in the commands at a configurable interval (say every 2-3 seconds) and report 2 signals to the circuit network:

1. ghost signal "G" = number of items that are still ghosts.
2. deconstruct signal "D" = number of items marked for deconstruction.

you capture, x,y,w,h only once on command trigger and you hold and report previous G,D (even zeros)

https://mods.factorio.com/mod/GhostScanner

You should sheck this mod out. It might be able to do what you are looking for. I used it in a self building factory and it did the job.

It might not show deconstruction process, but there bot count should be sufficient.