Dynamic batching - different vertices

Mostly trying to understand under what conditions objects are batched.

I understand that things like houses and such that may never change are idea candidates for this.

1. What about objects that rarely change? Like in a RTS game, where you can build walls. Should these be marked as static also, even though occasionally they can change, be removed, new ones added, etc.

2. Batching. Let's say I have a flower prefab, but I wanted to slightly modify the vertices of each instance that is placed in the world. Maybe one will have the leaves drooping more than another.

Does this pretty much destroy batching for this object? I'm not adding or removing vertices, just shifting them a little.They will share the same materials. I understand dynamic batching would handle this, but the docs don't say anything about moving vertices around.