First for injury poisons they are listed as three actions as the activation. I assume this is the initial application of the poison as it states that once applied it lasts until you attempt a strike with the weapon it was applied to. They don't list a duration so can you just apply your poison to your weapon during downtime and then have it go off when you first hit something with it? It I guess would make sense then as reapplying poison in combat would be fairly tricky so the three actions is probably warranted to reapply.
Second inhaled poisons. It says they go off when they are released from their container. Can you throw that container like a bomb? It seems odd that you would release a nasty inhaled poison by having it in your hand when you open it up. You can still work around it by inhaling deeply action THEN opening it but still seems like it would be more sensible to toss it and then once it breaks have it deploy the gas cloud.