Out of these I'd say pear is most likely, possibly a crab apple or plum also so not narrowing it down much! It's 100% not an Acer at least!

That's the fruit developing post-flowering, not a budding flower btw, so go back to see how it develops and you should get a pretty good id soon. I don't think plum fruits would look like that and crab apples aren't typically so long stalked and more often in bunches, but I wouldn't expect any plum/pear/apple to be so long stalked eitger, so perhaps a variety or species I'm not familiar with! Don't know anything about Brazilian plum or mountain date though.