Given the quality of the information that has made the current search area the current search area, a single P8 seems to be an appropriate commitment of resources from non-locals.
If and when there's definitely something to see, then a more substantial presence from the airframe and engine manufacturers could be justified.
A game of hunt the faint deep pinger would probably interest most well-equipped navies, with substantial kudos available to the winners; as well as the satisfaction of doing something very concrete for the safety of those millions that take to the air every day.