Clambaby came up with the rules for this which are as follows:-
Prep week: Friday August 14th from 7:00 am wherever you are to Thursday August 20th 11:00 p.m.- Cut, mark and interface any of your garment fabric - any activity that in fact does not involve actual needle piercing fabric sewing.
Sewing week: Friday 7:00 a.m. August 21st wherever you are and ending 11:00 p.m. (really we shouldn't be sewing till midnight) August 30, which is a Sunday.
I think your original rules Ruthie are good ones, amended to four pieces that match of any combination, for example three tops and one bottom are fine, as are three bottoms and a purse - all that matters is four things that if you wore the two of them on the same day together would not be upsetting.
No rules on pictures or posting, but if you can put up pictures on this site that would be good because we are nosy.
The prize is that if you complete four compatible pieces by the deadline you get to go out and buy for yourself a yard (or meter) of fabric you really want - one for each garment completed, so that means that every finisher wins four meters (or yards) of fabric that they really love. If anyone in the family asks why you are buying more fabric you can quite truthfully say that it is because you have won a contest. Personally I think this clause is bullet proof.