One thing you need to realize is that if there is any mixed seating, you may have a large number of guests who will decline to attend the wedding since their (via their rabbonim) personal position is to decline to attend any wedding with any mixed seating.
From a practical standpoint, mixed dancing is strictly prohibited according to all sources. And men being in view of women dancing is strictly prohibited. That being said, how will the men be precluded from viewing the women (in the mixed section) dancing? If that cannot be prevented, it is halachicly prohibited according to all sources.