I've never heard of using rubbing alcohol, but I routinely soak onion bulbs in a 5:1 water/bleach mixture for about 5 - 10 minutes before planting. This kills viruses on the outside of the bulb, reducing virus load and letting the bulb grow bigger. (Because multiplier onions and garlic don't go through a seed stage, the bulbs can steadily accumulate viruses over many generations.)
Garlic benefits from a certain amount of cold "chill hours" before growing the next season. It's called "vernalization", and comes about because garlic is adapted to colder climates. The refrigerator/freezer advice sounds like an attempt to fake this, but since garlic wants 4 - 8 weeks at low temperatures, it would have to be a pretty long exposure. If you live in a zone with a normal cold winter, there's no need to use artificial means of chilling. Just plant in fall, preferably a week or two before first frost, and it will take care of itself.
Garlic wants good soil, but it's very hardy. Don't overthink it. If you do what worked for you before, it's a good bet it will still work for you in the future, even as you learn more things.