enables more ignition timing
I doubt if too many tanks still have a lot of lead/tin coating left in them but the stuff is an oxidizer so it will definitely promote moisture absorption and corrosion. It's nasty to pot metal or about any other soft metal due to the oxidation so it would be hard on any remnants of lead/tin that might be still in there. Tillotson carbs or other fuel system parts made from zinc die castings wouldn't like it much.
A model A engine could run on straight alcohol but it would have to have some big jets in the carb to do it. It would likely get about 8-miles to the gallon or worse but it would run.
I live in an area where I can get real gas that is alcohol free, so that is all I use in my Model A , lawn mower and chain saws.
You are right about starting on alcohol. Ether is the usual way to start one but few folks mess with stuff like that now days. Ford tractors could be set up to run with kerosene back in the war time era. Up in southwestern Kansas where I'm originally from, they used to run casinghead gas from the natural gas wells. The stuff was a lot like running kerosene.
Stay far away from the stuff.
Brother-in-law ran it in his brand new Chevy pickup and by the time he had 60,000 miles on his truck it was back in the shop with major engine problems. The Chevy mechanic, first thing, asked him 'You aren't running E-85 are you?'
Brother-in-Law said 'yes I thought that was a good thing' they told him never ever use that crap again and showed him how it screwed up the motor in his truck.
E-10 is hard to stay away from. If you use MMO and a good fuel stabilizer like Startron that the outboard motor boat guys use that helps a lot. Buy straight gasoline when you can.