How can I make it so the lowest circle thing (armature?) on the bones in the spine is the parent of the highest armature in the leg? Is that even something I can do? When I try to parent it in the settings for the Bone, it parents it to the bone directly above the bone instead of the one under it.
Your bone is correctly parented, when a bone is parented (child), there's a dotted line that goes from its head to the tail of its parent. So maybe I haven't understood your question correctly but it looks like you're good.