COUNTIF vs COUNTIFS vs SUMPRODUCT

Yeah, it looks like a bunch of dates were being recognized as text instead of numbers. Is there a way to force a formula to read it as a date, though?

I mean, I can go through and use something like DATEVALUE and manually change each date that needs it, but the spreadsheet is edited by several people. If someone ends up putting dates in as text, then these formulas won't work...

Edit: Actually, it looks like I can just use Data Validation to force those columns to only accept numbers. That should fix things!