One reason why the other birds that couldn't compete with the honey creepers fared better on other islands is because the other islands didn't have the honey creepers. There was also enough food on the other islands for the other breeds of birds. The birds were also adapted to the other islands like the honey creepers were adapted to theirs.
Sedimentary rocks are made from eroding other rocks and they are deposited on other rocks, they are younger than the underlaying rocks hence could only be formed on older underlaying rocks. If u have any more questions feel free to ask!