Hi is there any explanation of how character and weapon stats work and what they do ?

Coming back to this game after years, I dont think I can even find my original disk.
Anyone knows if there is some guidebook or readme that explains different stats on characters, weapons?
Manual that comes with the game explains these things very poorly.

Health is health, strength increases your carry limit.
Then there is
Speed
Reaction
Accuracy
Stamina

I tried different Stamina and Speed (highest and lowest are around 50 and 90) but both my squadmates seem to move at the same speed.
Is this only multiplayer thing, and if you play solo your AI companion moves at the same speed like you?

Reaction I guess is AI only, but what about accuracy? Does it affect you too, or is it only AI thing again?

What about weapons? What are their differences ?
Weapons I understand they give you more options, but do they also increase damage or accuracy or something? Is it better to bring higher tier weapon, or is it waste of tonnage if you dont use grenades/rockets/mines in some missions?

(And bonus question, does the online coop work or not? Theres tons of different answers all over the internet. I tried few things but if it works it seems like you need something like Hamachi or something.)