Rabbits are the very model of prolific breeding, and springtime is when they really ramp up. Eggs are important because chickens generally don't start producing eggs until the daylight is longer than night - i.e. after the spring equinox. The only reason we have eggs year-round is due to artificial lighting. And flowers are self-explanatory.
There's also the timing: Easter is always the first Sunday after the first full moon, after the first day of Spring. Aside from the nominal 'Sunday' addition, this is one of the most 'naturalistic' ways possible to derive a holiday.
The current celebration is highly religious, but it's a far cry from 'legitimately Christian'.