Does Trample Damage Go Through Indestructible?

Gracias! Indestructible creatures still get assigned damage, so the rest can still trample through.

Does indestructible stop trample damage?

Even though an indestructible creature isn't destroyed by lethal damage, that definition is still used for things like assigning trample damage. If a creature with lethal damage on it stops being indestructible, it's destroyed the next time state-based actions are checked.

Does trample damage go through protection?

Yes. If you attack with 7/7 green creature with trample, and they block with a 2/2 protection from green creature, it will assign damage equal to that creature's toughness (2) to the creature, and the other 5 will trample over to the player.