Case tracking table

Hello everyone, and thank you in advance to those who will take the time to respond...

Here is my question:

I work in a Notary Office, and I would like to create an Excel file that automatically optimizes my work in tracking cases. To do this, I would like to create a unique file that functions as follows:

1°) FIRST QUESTION regarding my first sheet:
General table with all my ongoing cases and planned in columns:
1/ Type of case (I created dropdown menus such as sale/divorce, etc.)
2/ Case name (to be filled in manually upon creation)
3/ Author (initials of the author, I created a dropdown menu)
4/ Opening date
5/ Expected signature date
6/ Progress of the case
7/ Fees

Regarding 4/ and 5/:
I would like to create an automation so that when entering the opening date, the expected output date is automatically generated based on the type of case (1/) entered.

For example:
1/ Donation
2/ XX
3/ XX
4/ July 13, 2014
5/ => Automatic calculation: I will have indicated somewhere that a case of type "donation" takes 20 days to process, so that the table indicates on its own in 5/ "August 2, 2014".

2°) SECOND QUESTION REGARDING THE Following Sheets:
I was thinking of creating a sheet for each month of the current year.
To extend the example, let's take the "August 2014" sheet

Since, on my first sheet, the output date of my "Donation XX" case has been set to August 2, 2014, I would like this "case line" created in my first sheet to automatically integrate into my "August 2014" sheet.

3°) THIRD QUESTION:
Is it possible to have a sort of checkbox in a column to indicate that the case is archived and, by doing so, make it disappear from sheet 1 and from the "current month" sheet to transfer the line to an "archived cases" sheet?

4°) Fees field on sheet 1:
I will enter the amount that the case brings to the Office. If I enter it on sheet 1, I want it to be reported on the month of the signature sheet, and vice versa.

Knowing nothing about programming, it seems utterly impossible to create such a document, but I count on you ;)

Thank you in advance,

Upsilon