Ghost knife get too big for your tank, so I think not. Also, African Clawed Frogs can get quite large and have a tendency to eat any fish that will fit into their mouths.
Ghosts get very large but take ages to get there and catfish is right there better left for the experienced fish keepers, seeing as i dont know what a dawrf frog looks like can you show me a pic? because maybe a pair of rams could go in there or maybe just one.
This is an example of the 2 albino african clawed frogs I own. They are mildly aggressive but only during feeding periods, so arguably something robust and semi-aggressive aswell may be ok.
I did own 3 2inch Tiger Barbs with them who were fine