Hibana's gadget is the X-KAIROS launcher. You use it to open holes in reinforced walls or open a reinforced hatch. The X-KAIROS launch can shot three volleys of six X-KAIROS pellets. You can use the gadget anytime and anywhere.
Echo's gadget is the Yokai drone. The drone can attach to ceilings and when attached to a ceiling, the Yokai will become basically invisible, but you are able to spot it if you have a good eye.