Hi.
The best way to ask questions about mdadm is to send mail to linux-raid@vger.kernel.org. However I do sometimes reply to questions posted here.
When you --create an array, and pre-existing data is not destroyed, at least not necessarily. If the 'resync' process that usually happen on array creation starts, that could destroy data, so while experimenting you want to avoid that.
For a raid5, the best think to do is to create the array with one device listed as "missing" rather than "/dev/sdwhatever". That way the array will appear degraded and no resync will happen (For raid6 you would want 2 'missing' devices).
So I suggest you try creating the array with various combinations of drives, always having one 'missing', and try "fsck -fn" on the array until you find a combination that fsck doesn't complain about.
The order of the drives is very important, so try different orders until it works.