1) I dont follow. Where is it showing the date in the incorrect format? on the details page? results page? please provide more details and a screen shot.
2) On the details your if statement is using 2 separate date formats:
<?php if (date('D F j, Y',strtotime($row_WADAtbl_post["eventdate"])) != date('D n/j/Y',strtotime($row_WADAbrevents['enddate'])) && $row_WADAtbl_post["eventdate"] !='' ) { ?>
you are using D F j, Y for eventdate and D n/j/Y for enddate. in reality, you should just be using the timestamp generated by the strtotime command:
<?php if ((strtotime($row_WADAtbl_post["eventdate"]) != strtotime($row_WADAbrevents['enddate'])) && $row_WADAtbl_post["eventdate"] !='' ) { ?>