Do both my partner and I have to be practicing Christians to have our child baptized at Metropolitan?

No. Both parents do not have to be practicing Christians to have your child baptized at Metropolitan.

You may also want to consider the option of a Celebration of Birth, which is almost the same as a baptism without the trinitarian formula. This rite of passage enables a family who may blend Christianity with another faith tradition to bring a blessing to their newborn without compromising the belief system of either parent.