The methyl isobutyl ketone (MIBK) must be removed prior to use in an Al/Hg. It will otherwise react with either your methylamine (forming 2-methylamino-2,4-dimethylpentane, which will contaminate your product if you aren't distilling your freebase), or it will react with the formed MDMA, forming the inactive N-(2,4-dimethyl)pentane derivative, which can be hard to separate from your product.
MIBK has a bp of 117-118°C, but it probably forms an azeotrope with ethanol. According to a source on the net, your mixture is probably 90% ethanol, 9% methanol and 1% MIBK.
I'd say that pre-reducing the alcohol mixture with Al/Hg would turn the ketone into the alcohol, which won't interfere with your reaction.