It depends on the OG/SG. If you already have a pretty high %ABV, it's unlikely the bottle dregs will do very much on their own. If 12oz is all you have to work with, you could make a starter with 12oz and the bottle dregs, wait 4-5 days and then feed a bit from the carboy every few days until it is accustomed to the higher alcohol. The whole mess can then be returned to the carboy with hopefully a much higher population of bugs than you would get just from the dregs.
Good point. That is why I've opted for making a "starter".
On a side note, I just discovered that Liefmans and Lindemans are both pasteurized before being sold.

I still plan to pitch the dregs of the bottles I have from them, since I've heard Brett can be pretty resilient, but I'm not gonna hold my breath.
The De Proef Zoetzuur was delicious, and had a good sized cake on the bottom of the bottle. I even had some Brett (little white flakes...I think it was Brett

) floating in my glass.
Sanctification was also added yesterday. I have to say, I've never seen such a weird beer in the glass! The carbonation bubbles were much larger than normal, and behaved differently than I have ever seen. Basically, as the bubbles rose, they formed a film of bubbles on the surface. Not like normal "head", did not dissipate or break apart after swirling. After the film formed, I could sit and watch new bubbles rise up and get caught underneath it. It was very cool to look at.
The mother culture is now visibly fermenting/bubbling on the surface. I plan to move this into the New Belgium/Allagash Vrienden 22oz soon, for two reasons. First, I've read all of the Lips of Faith series from NB have been pasteurized, so if there is anything left, I don't want to risk loosing it to the sides of the bottle when adding it's dregs. And second, I am running out of room for more additions into the Cuvee de Tomme bottle.
