May be I find difficult to add the date formatting as per the snapshot you attached. When the number tab is clicked on the expression only appear not the dimension such as Date1, 2 & 3, May be the way I proceed is not correct. Con you please explain a bit on this. Also, You had suggested two data loading, once 1st loading was done, Data_2 still appeared as a value. Also under 2nd loading instead 1st, for date_2, you have not brought the same formatting we did for 1 & 3 dates . Could you please say why it is so?
In first load I used all three date fields as dimensions. Yes for dimensions you can't use Number tab of chart property. the second date field is as per US format so Qlik recognized it without the need to explicitly format like the other two. In order to display as date you may have to play with it in the front end / may be explore default date settings in Qlik and/or System.
In the second load I wanted to use three date fields as expression to utilize the number tab on the chart property and set the format manually.