Removing devices doesn’t actually remove them from the hub. For the dimmer, you will need to do a general exclusion before you can include the device again. And for the bulb, you will need to reset it.
Here are some tips for the dimmer:
https://support.smartthings.com/hc/en-us/articles/200879274-How-to-connect-and-reset-a-GE-in-wall-switch-or-dimmer-Z-Wave-
And follow these steps for the GE bulb: