Cellar Dweller

Most of those can handle time sitting, but I usually find that tripel styles don't do quite as well over time.
Even styles that are supposed to age well, some individuals don't necessarily improve over time.
Can I presume that you have a box from 2010, 2011 etc also sitting around?
Also keep in mind that not all beers need 5 years to age. Some don't age well at all (it appears you know this) some only need 6 months or a year to be at their best then go downhill, others will do well over multiple years.

 

It's not as much by style as individual beers.
I find that I prefer the brightness of saisons fairly quick after bottling, say, under 6 months in general, but that does depend on what flavors and esters are in the finished product; like I said, some are better than others after x amount of time. Tripels can last a bit longer, maybe to about a year.
lighter stouts, porters, British styles and other malt forward beers are best within a year - again generally, some can take longer, others are best fresh.
The only styles I really like after a long time are in the Russian / Imperial stouts, dubbels / quads, barleywines and most sour styles.

 

Chill um and taste em. you will know soon. Duvel I would wonder how well that would age. I sort of agree on the tripels too much age on them ruined them IMHO. the Chimay on the other hand should be outstanding. I had many an old Chimay @ Kulminator (Antwerp) over the years. great stuff.