In only discussing Percocet vs. oxycodone, percocet is oxycodone in combination with acetaminophen therefore it may potentially be more effective than oxycodone alone though it would depend on the resident's interpretation of "stronger". If they are asking about overall pain relief, percocet is probably better, but if they are asking about neuro-active ingredients then they are equal.
What you need regarding the other medications is an equianalgesic chart to compare the strength of the narcotics you mentioned. I'll let you google that, there are many out there. Generally they compare the strength of many different pain meds to 10 mg of morphine as a baseline.