Neither one of you can decide if you want to date each other, so you basically put your life up for vote to a crowd of people, some who you don't know?
Not sure if that's more lame or more novel. Either one or both of you are too scared/unwilling to go out and find someone else to be with so you default to what's easiest/safest.
You'll probably end up being one of those couples who break up, then get together, then break up, rinse and repeat. If that's going to be the case, just pick option 3.5; essentially an open relationship. Then you can basically do what you want with whoever, whenever. Of course, if either one of you have even an inkling of jealously, this option will fail.
If both of you plan on manning up and actually giving it a shot, then pick #5. IMO, going to such an extreme of picking #6 just makes you retarded and you will be nominated for it. It would be a waste of $, if you don't even really care for each other.
OTOH, if MM presented DG with those options then it seems that MM is more desperate of the two. In that case, DG can just be a XXXX tease and string MM along. Then again, I know neither one of you so for all I know you both are willing to enter back into your relationship and actually make it work.
That's my .02.