Linked worksheets: Add columns across all sheets with auto data updating & formating

I am working with month to month data (so the # of working days changes) and I need the columns to update with them across all sheets.

My layout is a source sheet and tabs with linked data to create easy snap shots to send out to the individual stores to let them know how they are doing.

Is this possible? There are 26 stores so that is a pain to auto fill on my part as I update each month with column changes.

Lastly, I create snap shots of their weekly totals... but again work weeks change depending on where the 1st of the month starts! Any ideas on how to go about that one too? If not, the linking of the new columns would be AMAZING.