If you are willing to take a chance that construction finishes as scheduled, the Peninsula Tokyo is opening around that time.

The PHT limits the number of weddings they do and usually sells out well in advance, so if that's one of the places you're interested in, you can't take forever to make up your mind. The other luxury hotels probably run out of slots well in advance too except maybe for the FS Chinzan-so which seems to be VERY focussed on this business every time I have been there because, I presume, of their generally lousy location for many other purposes.