index/match, Sumproduct and a dynamic list

Hi All

Can anyone help me with this, I need help with the following formulas....

1. I need a formula on the “summary” sheet (column A) which is returns unique customer numbers sorted smallest to largest. However I need it to be dynamic in that it looks up the last row automatically. Red highlighted cells
   
2. Once I have that list in place I need an index and match formula which would match the following on the summary sheet: customer number (column A), column number from the condition in cell A1, month number (cell A2) and the Forecast numbers (Row 3) with the corresponding data on the “Data” sheet. Green highlighted Cells. the added complication for this is that if "All" is selected in the month field (rather than an individual month) i would need all months returned if this is even possible?)
   
3. Formula 3 I think would be a sumproduct formula which is on the “individual sheet”. Here I need it to subtotal column L on the data sheet but I need it to match the conditions (customer, month and forecast) on the data sheet.

I am never the best at explaining what I need but I have uploaded a spreadsheet which shows what I need.

I know a pivot table can achieve this easier than formulas such as sumprouct and index/match however I want to avoid using them as this will form the database of my model

I know its cheeky asking for three complicated formulas but If you can help with any of the above formulas it would be appreciated!

Paul