In my experience, Animal Companions for Gestalt characters seem especially underpowered. As the DM, I have a 2-part plan to address this.

1. Max out HP vs Rolling
2. Allow Gestalt Druid/Rangers to combine levels for determining companion statistics. This means a level 6 Character can have a companion equivalent to a level 9 Druid.

Limitations, this is for an E6 campaign so the given example is the high extreme.

1. Does this seem too powerful?
2. Are there established methods to resolve this issue I am unaware of?

Edit: I am the DM of this small adventure; I thought that would be understood by the changes I was trying to implement but since I didn't make it clear I've edited the question to state it explicitly.