From what the product of 'theoretical ammonium hydroxide' and aluminum are, to the debate whether ammonium hydroxide exists or not. Haha. It's actually not with the name. It is the reaction of ammonia and water that there is a production of ammonium ion and hydroxide ion (though some part of the hydroxide ion production is due to ionization of water itself). OF course both ions exist but as I have said it is not with the name. There is no such evidence that ammonium ion clings to the hydroxide ion. They coexist in solution. In the question whether what would be the product, I haven't tried putting aluminum to ammonia solution. But most probably, aluminum hydroxide will be produced (I just don't know if it would really take years).