Autofilling or creating a dropdown menu for a monthly shift schedule

Hello guys and galls,
First and foremost I would like to thank you for your time.
The situation is this:
My wife is taking a long time (more than 10hrs per month) to plan a work schedule each month.
Now, it ain't easy what I'm about to ask you and I know this because I am a more than basic Excel user myself.
With no further ado I attached the current sheet she is manually working on.
Monday to Friday there are 3 shifts that need to be color coded (blue the morning shift, green dayshift, and red the nightshift). On the weekend there are 2 shifts only but have a special rule that says no less than 24h between the shift of a worker.
Each shift has 2 different type of workers and each shift will have both types of worker.
There are also the vacation days that need to be filled.
Is there a way to automate the process if enough amount of data has been preset?
I'm thinking about this solution: There is a shift for each individual worker that my wife fills at the start of the year with the vacation days. so we got that figured out.
This month shift sheet needs to remember last day from the previous month shifts in order to autocomplete the shifts.
In order to be correct it should know that any worker can't have more than X amount of working hours per month.
Please notice that there's a line between worker 12 and 13 i drew it to separate the 2 types of workers.
I am pretty certain that an automation would be difficult to implement but what about some dropdown menu or some sort of help in order to calculate/draw the schedule in much lesser time?
Anyway thanks again