Ok, my fermentation temp started dropping, signalling the yeast were slowing down on fermenting so I decided it might be about time to add the cherries. Run to the store to pick them up to find out they no longer carry them... run to a different store and they only carry them online. So, I pondered ordering online from a couple different places and figured the earliest I would get them would be Mon-Tues, which likely would be fine, or I could use cherry juice if I could find some without any additives.
Found these, which both labels showed they only contained 100% cherry juice:
http://www.rwknudsenfamily.com/products/single-fruit-juices/just-black-cherry
http://www.rwknudsenfamily.com/products/single-fruit-juices/just-tart-cherry
Did a quick search and found a few posts about people using these in other beers in place of cherries so I ran with it. Poured both bottles in last night and noticed fermentation temps went up 3 degrees overnight. @Poptarts said his recommendation would be to go with 3 cans of each type of cherry and after some research I found that each bottle should be equivalent to 3 lbs of cherries, so it should be about the same addition as 6 cans would have been.
I did forget the sugar so I'll likely boil the 1lb of sugar with a small amount of water, cool and throw that it tonight or tomorrow morning. I also tried to grab a hydro sample to figure out how far along it is, but got more krausen than anything and didn't want to keep fussing with it.
As for vigorous fermentation, this yeast (WY3463) has yet to exhibit that for me. In the Wit's, Tripel, and now this that I have used it on the most I have gotten is with this beer, but so far that's only about 1.5-2in of krausen. Seems to do it's thing pretty quickly and quietly compared to many other Belgian strains.