This A380 would need a thorough inspection, but no reason it cannot do a 3-engine ferry with just a bare pilon and no engine. As long as all the ancillaries are secured, it would be easier without the engine than with. One of the prime reasons for the fat cowling on jets, is to reduce drag after an engine fails. Having no cowl would increase drag beyond the 3-engine ferry certification data.
While I don't disagree, the problem would be did Airbus bother to certify 3 engine ferry with the engine completely missing (my money would be no). I'm familiar with the 747 3 engine ferry, and it all assumes the engine is there. It'll probably be easier to do the needed repairs on site than to get the necessary certifications to do an "engine missing" ferry...