Data Validation between Workbooks

I have two workbooks I'm working with. One is the input/output spreadsheet and the other is the data spreadsheet. The inputs are dates, the outputs are decimals.

What I already have is a few macros that will look up the dates from the input cells into the data spreadsheet and output the results from the matching dates. The issue is that not all dates contain values to output (like on weekends/holidays/etc) so if you input an invalid date it blows up the macro.

What I would like to do: Have a control to click after inputting values that put the number "1" in the column next to it and shade the background of that cell red as well. If you have all valid dates, I would like cells D5:D7 to say:

ALL
DATES
VALID

If you have some ideas about how to write this macro, it'd be much appreciated. I was thinking of doing an if(vlookup()) combo but not sure if that's the best way.

I've attached a sample to show what I'm talking about. The first tab will be the input/output and second tab will be the Data workbook which will be a SEPARATE workbook completely. Just added it to the same file here for simplicity.