Pete,
It's fine to go ahead and bring them in once the leaves drop. One word of caution though, very young figs are often reluctant to go dormant. If this is the case for your trees, I'd suggest bringing them in on nights when the temperature dips down to 32*F and below, and return them outside to enjoy the warm days. Once the night-time temperatures settle into the mid 30's for good and you're tired of bringing them in and out, I'd pinch off the leaves and put them into storage. Don't forget to water them from time to time while in storage so the potting medium doesn't become too dry.

I would sugest take fertiliser Back out,but put limestone powder in top.
When they grow new roots and establish themself in a new pot,mix the fertiliser does not help,but by the contra it hinders the production of strong roots.
Fertilising,yes next Spring after they leaf out.!