1 oscar1 tiretrack eel
1 black ghost knife
a few bala sharks or tinfoil barbs
4-5 clown loaches
3-4 elephantnose
1 synodontis cat
1 pleco
Personally, I wouldn't get the Elephantnoses or the ghost knives. Both can be touchy about water conditions, hard to feed, and are rather shy.. not really a good combo with oscars.
Also, both species emit electrical currents which can disrupt things amongst themselves. Elephantnoses can also be very territorial with one-another. Only 1 elephantnose OR 1 ghostknife should be kept because of these reasons.
HTH