Usage and notes:
Catwoman prompt: 1girl, catwoman, green eyes, animal ears, dark hair, collar, breasts, cleavage
Optional tags for Catwoman: gloves, goggles on head
Recommended negative tags for Catwoman: scar on face, tail
Batman prompt: 1boy, batman, mask
Optional tags for Batman: cape
When prompting for both characters, I suggest starting with fewer tags for both. For instance, you can start with this: 1girl, catwoman, animal ears, 1boy, batman
Recommended negative tags when prompting both characters: claws, scar on face, tail
You can use adetailer's [SEP] feature to give each detected face a unique prompt when prompting for both characters.
For full prompt examples, look at metadata for the image uploads.