The Emoriim got squashed through the two mountains coming together not a flattening. So one can answer either that the “Anan” only flattened the mountains that Bnei Yisroel passed through so as to lessen the effort of travel but here they traveled around so there was no need for these mountains to be flattened. Another possible answer is that this maaseh was right after Aharon died and the Ananim went away (which were in his zchus) so there was no Anan to flatten.
Simchah- I heard that Bilaam hated the Jews even more so he wanted to curse them in a more severe manner but Balak only wanted to save himself so he just asked Bilaam to perform a light curse.
Haleivi-I am not sure why you switch back and forth between the aron doing the flattening and the ananim