What variables of an evolving Pokémon remain the same?

Question

When a Pokémon evolves, a lot of its attributes change, such as types, base stats etc. Some, however, like egg cycles and leveling groups, stay the same.
Are there any other attributes or values that stay the same?

As an example, a Bulbasaur levels up medium slow, and needs 1059860 EP to reach level 100. These variables remain the same even when it evolves into an Ivysaur or Venusaur: they all level up medium slow.
They all also need 20 so called egg-cycles to hatch. If you hacked an egg that contained an Ivysaur, it would take just as long to hatch as a Bulbasaur would.
These values are constant and don't change during evolution, they are unique to each evolutionary family.

Those two, however, are the only attributes I can think of right now, and I just want to know if there are any other variables that remain the same among each evolutionary family.

Answer 1

Looks like it's just the amount of experience needed to level up to 100 and the number of egg cycles needed to hatch.

• Capture rate can change
• Gender ratio can change (most obviously, in gender-specific evolutions like Gallade and Vespiquen. But also for Azurill and Marill)
• Base happiness can change
• Egg groups can change (for baby Pokémon like Pichu)

Everything else, like types, stats, and abilities, obviously changes in many cases.