Those will work for manipulating the actual data.
Along with the text functions you can convert the date/time to string , manipulate the string to have what you want and reformat it into a date/time that you want.
if all you want to do is control display...
Did these dates come in as text or dates? If they came in as dates, then FM actually stores how it was originally typed as well as an internal date number. So FM treats a date the same no matter how you formatted so long as FM was able to properly import it as a date. What I usually want to do is have a date field all formatted the same way. In the layout, click on the date field and go to the Inspector and click on the Data tab. At the bottom, you will see the options for formatting a date in a layout so that they all look the same in that layout.
I personally prefer MM/DD/YYYY with leading zeros and 4 digit years. So this is what I do for a date field in a layout.