I can't see why not, just don't mix it up to keep that blanket of Co2 in place.
I would split and scrap the beans, just in case you did not know, and depending on the bean they can be pretty strong. I would consider using just one for a week. Then racking / bottling to seal them up.
The problem with vanilla is it is very strong at first, then weakens over time and I usually just use it as support for other spices like nutmeg and cinnamon.
Best of luck,
In Primary: Belgium Chimay clones.
In Secondary: Braggot, pale ale, end of the world white.
Conditioning: Mead, Cider, braggot, Belgium Wheat.
On Tap: Clones, Chimay Blue, Red, Porter, malted cider.
Bottles: Far, far, too many to list.