I have a level 6 Druid and I raised his companion's Intelligence to 3. Do tricks even matter anymore? I'm not clear on whether they are still necessary for combat training or use as a mount.
All the tricks it already knew should still apply.
Do you have a way to reliably talk to the creature, and do you think its 3 Int will suffice for it to understand and comply with simple instructions? Then further training is unnecessary. It's still possible though.
Paizo blog on animal companions
Tricks still matter, you're still supposed to use handle animal. You do however get 3 additional tricks for the point of int.
Putting a rank in linguistics will let the animal understand a language but not speak it.