Who were Darren and Kelly?

[HomeandAwayFS]

I was watching episodes from 1990 and I think it was episode 500 when Sophie wasn't yet fostered by Pippa and Tom and she was walking with Sally and talking to her about fostering and then Sophie asked Sally about Tom and Pippa other foster kids and Sally mentioned that first there was Frank then Darren and Kelly and then Carly Sally and Stephen etc. But I wasn't sure who Darren and Kelly were.

Does anyone know anything else about them? Have they ever appeared on screen?

[Red Ranger 1]

I think everything we know about them is in that scene, with Sally casually tossing their names out there with a "but they didn't stay very long."Certainly we've never met them.

[Blaxland 89]

I think there is more info in them in The Frank Morgan Story.