restoring site on local drive that uses multi-DB

I am working with a developer who wants to replicate our a few our our sites on their local drive. We currently have the Multi-DB plugin (256 databases) active. The developer is having issues getting this set up on a local drive. Here is the problem:

– Where & what files in SourceCode need to be configured to map the local database, which are restored

– The developer has completed downloading WordPress SourceCode and Database backup, also changed a few configuration settings to map the WordPress backup site and local database.-

– Developer is not downloading all sites to local drive, rather 2 out of the 900+ sites within MS

– After configuration made in local environment, we are still getting “Error while Connecting to database”

Can you provide me with any tips on how to replicate the site in a local environment? Why are we getting an error message?

Thanks for your help.