Fahrenheit being closer than Celsius is subjective. Do you understand?

Given that you already said you have to use 3 digits to give Celsius the range that matches human temperature sensing, that's not true. 1 degree F is the average threshold that humans can perceive a difference in temperature. It's why thermostats use 3 digits for Celsius but only 2 for Farenheit.

The only reason you say C matches people is because you are used to 21.5 C being a regular indoor temperature. If you grew up with Kelvin that would be 294.5 K. Three digits instead of four.

what is your minimum and maximum

Doesn't matter. Base 10 would be better so it matches the rest of metric. The decimal place shifts one space but that doesn't change the number of digits needed to represent a temperature.

Zero is absolute zero. You can't have below zero because temperature is a measure of motion.

how do you scale

Linear to match the rest of the metric system.