The old method of adding a small % of your hops while the kettle fills is supposed to help but I've not noticed a difference. Plenty of headspace in my kettle so I just knock down the foam with a mash paddle. I'll have to try the water spray.
If you condition it for a year, it's bitterness will drop to 75% of current. Also you can retain 1/3 of your total hops and add them to the last 20 minutes as aroma hops. Have you used software to calculate your IBUs?
I only know this because my friend brews Belgian tripels and its the only beer he bottles. Because it traditionally has a very high carbonation level he bottles in champagne bottles and corks them. Regular bottles would explode.
Since you're not detecting diacetyl you could go with a more traditional approach and slowly reduce temps to lagering over several days. If you want to do a D-rest, not always needed, now would be the time since you're over 75% attenuated.
You'll get some debate here about rehydrating yeast. Supposedly if you don't you lose some small perentage of cells, however IMO most packets account for this loss in their present cell count. So pitching dry should be fine if you "rock" aerate well. Pumpkin Barley Wine sounds really good...