I will not argue the economic or thermodynamic aspects of ethanol addition to petrol, but as a chemist most of my working life I challenge the assertion that ethanol is "extremely corrosive". It that was true it would be undrinkable, and given that ethanol is the active ingredient of all booze I don't see millions of people dying after a couple of drinks. Mankind has been making, pumping and storing ethanol for hundreds of years so there are no insurmountable problems in handling it.
No, the fact is that ethanol is a different sort of organic solvent to the octane and related hydrocarbons that comprise petrol, and therefore requires different materials to be used for its storage, pumping, sealing, and injection. It would be easy to design and build a fuel system for ethanol, but our problem arises from trying to run ethanol in existing systems designed for petrol. It is similar to the situation when tetra ethyl lead (the anti knock additive) was eliminated from petrol many years ago. Older cars at the time suffered erosion of the valve seats because they relied on the additive to seal them; newer cars were designed with harder seats and have had no problems ever since.
With regard to emissions from alcohol fuelled engines, there will still be some CO2 because alcohol contains carbon, though proportionately less than petrol. As for nitrous and other oxides of nitrogen (NOX) I do not know, because the generation of NOX depends on the combustion temperature and efficiency of the engine; high efficiency engines create more NOX than low efficiency.