try the "update preview" button in the AE, that usually works for me...
I hope that helps..
And for the second one, you CAN change how it displays in the viewport, but it slows down the scene considerably.
As far as rendering goes, make sure that you are applying the texture where it was meant to be applied, because layers and such often mess up how it displays any given other layer, and sometimes you need to play around a bit to get the texture to show..., and make sure that the texture is not a built-in Maya texture (checker, etc), as these do not work in Maxwell