You can't change companion weapons or armour

But once again, why do you bring a character you find unfit for that environment on that particular place ?
You can bring only two people on the field, so you should take those you see fit for the environment.

Moreover nobody in the AI knew the planet would be so hostile for life, remember that they were golden world.
If those world were totally inhabitable we would not stand there in the first place. Condition are harsh but are not impossible to go around.

The desert planet seem to have one of the harshest environement with the nomad taking damage under the sun. Of course Pee Bee would not last long in the sun, but neither any member of the crew. that is why everyone stay in the shadow in the whole time. Would every planet have condition so bad you could not stand in the open without dying ?
The New Zeland planet (Gameplay trailer1) seems to not have particular hazard except acid lake and dangerous wildlife.

Moreover in a world were you can have cryo ammo and cryo melee weapon, I don't see how you could not have a miniature cooling tech or implant to regulate your body temperature. I would expect a civilization with thousand of years of technological advance to our current technology to have resolved that small issue.
You can travel at more than lightspeed and resurect the dead but you cannot regulate temperature !