2 stoke engines typically don't have an oil sump or pressurized lubrication system. The only lubricant available in the crankcase is the oil/gas mixture. That oil/gas mixture has a lot of demand placed on it; it must lubricate the big end of the connecting rod, the wrist pin, the rings, the piston skirt and the two outer crankshaft bearings. The good news is because it's constantly being replenished; that gas/oil mix only has to work for a brief period of time. More oil improves the lubrication but it comes at the cost of less efficient combustion and less power. Like most things in life - it's a compromise.
If the bearings can stand a thinner oil mix then there's an advantage to running more gas and less oil. It comes down to what the engine can tolerate. A little more oil doesn't hurt much but it comes at the cost of smoke, plugs that foul easier and slightly reduced power.
As for alcohol and gasoline - The ethanol causes more problems in small engines than it's worth. It also causes huge problems with storage of fuel. Fuel stabilizer certainly helps but pure gas is even better.
Octane rating: this is probably one of the biggest scams around and it's easy to sell because people want to believe it's true.
High compression engines need high octane gas to run without detonation [knocking or pinging]. Increasing the compression ratio (to a point) is one of the ways to increase power but high compression requires high octane fuel to take advantage of that higher compression ratio.
Using high octane fuel in an engine that doesn't need it to operate; DOES NOT PRODUCE ADDITIONAL POWER. Putting high octane fuel in a low compression engine doesn't magically make it run better, stronger or more efficiently. In fact, it may even be less efficient.
When people buy high octane fuel and tell themselves that they are getting: more power, better gas mileage or some other perceived benefit - they are just engaging in a self fulfilling prophecy. They want to believe they are getting better performance so they do believe they are getting better performance. The fuel companies are happy to sell you more expensive gasoline and they are not going to educate you.
Now, there are some high compression engines that have the ability to produce maximum power on high octane fuel and compensate for lower octane fuel when necessary. Those engines have knock sensors and computer controlled ignition and fuel systems that reduce power output when they are fed lower octane fuel. However, a low compression engine that runs fine with 87 octane fuel will not magically produce more power if you supply it with 93 octane fuel.