Book the "event", then reserve rooms in yours, your new wife's (congrats!), and anyone else you feel like being generous to - as you will receive MR points from CC for every dollar spent, event points, however points from hotel for only 3 rooms each.

Yes, actually, that is a great idea! Set up a MR account for yourself, and for your new wife, and another for each of your parents, and assign the rooms reserved to those new accounts, in order to make sure to earn points for all of the rooms you wish to pay for in your room block, you can always transfer those points to your account later on. You will not get the extra 5 points for the credit card for those rooms, because the name on the reservations have to agree with the name on the credit card paying in order to get the credit, but still, you will pick up 10 points/$ spent for all of the rooms you want to, and you can transfer those points later. In the alternative, if you can arrange your hotel contract for whatever amount of points you are expecting to your own account for the rooms block, and then you don't have to go through all the multiple reservations for your new wife, parents, etc.

I have always thought it was a really bad rule to not be able to earn points for all rooms reserved AND being paid for by one person. If the OP reserves 17 rooms, and pays for 17 rooms, and especially if the OP arranges this in advance, for a wedding block, or some other event, then the OP should receive all the points for all 17 rooms. I have never understood why Marriott would want to discourage guests to book group events such as above, and not allow points earnings for all of the rooms in the group if being paid by one person. I understand not allowing room night credit for all of the 17 rooms, but not allowing points credit is total non-sequitur!