If you're new to Poser, modelling your own figures is probably too much. It's not easy. A lot of people who have been using Poser for years never learn to do that.

And you can't do it with Poser. You need a 3d modelling program (Lightwave, Wings3d, 3dStudioMax, etc.) Then you have to rig the figures so they're poseable. The learning curve is quite steep. I doubt you'll make anything usable by your deadline.

Maybe you can get someone to make them for you. For free or for pay.

You might reconsider the "jelly baby" design. Have you thought about what they will look like in 3D color? They'll look naked, unless you also model clothing for them (which is a whole 'nother headache.)