how to make network-wide updates in multisite

We are creating a network of sites using WP Multi-Site.

We’ve completed one site, and then, using an outstanding plugin, are cloning that site to create the other sites and then simply making a few changes (city name, in our case) for each new site.

There is a classified ad plugin that is being cloned to all the sites in the network.

My question:
In multi-site – – if we were to make modifications to certain aspects of the classified ad plugin setup, will those changes automatically occur throughout the network? If not – – is there a way (it seems there MUST be a way!?) to perform network-wide modifications in a multisite network?

Thank you!