You can replace both your formulas with this single one:
Use the following formula without the need of an extra cell. It also takes into account leap years.
I am the OP. I tried switch and it almost worked but I couldn't quite string it out right with that function. I searched through a function list however and found the IFS function and that seems to be working wonderfully. Thank you for trying to help pjmg. Sorry I didn't have more information and then quickly worked it out myself. I was stressed with trying ...
If you want it all in one cell you need to use Query:
=query(importrange("https://docs.google.com/spreadsheets/d/1q87c_0rFdt8FcWtIzD0KVW3k1ZpuvhfeWb1281MEs","DEMOS!A2:C1000"),"select count(Col1) where Col2 = 'Rep1' and Col1 >= Date '2019-11-9' and Col1 <= Date '2019-11-15' label count(Col1) ''")
It is not clear if you want to pull data from another tab of the document you are working on or you want to pull data from another tab of the "url of my document" and don't want to type the whole thing again.
Pulling info from the same document but different tab using query would be as easy as replacing importrange("url of my document"; "INPUT!A1:F28") ...
d/m/Y is an ambiguous date formatting.
It's very likely that this occurs because the spreadsheet regional setting used in the spreadsheet doesn't support d/m/Y as a date formatting. Please note that the screenshot included in the question shows column J values having a "day" value greater than 12, with exception of 11/01/2019 have the a white cell ...