If these are indoors, which I'm assuming they are, you don't need your filter on. You're gong to want to capture as much natural light as possible.

Hell even if you boost up your shutter speed and drop down your ISO, you'll atleast get a brighter picture. Since your subjects aren't moving, so that shouldn't be a problem.

Even your on-camera flash should give you a little bit of fill light. Hell, work with it at home and test it out. Couldn't tell you how many test shots I've done on my dining room table.

And Jake is right. $5 bedsheet from Wally World and you're good to go. Also you can pick up 24x36 foam boards this way your "floor" and back drop are the same color and you don't get any creases. Just watch the reflections with the foam board. I noticed that when I was shooting with it, so most of the time the sheet is a better choice.