Howdy ... sorry it took me awhile to get back.
I guess lets start with Limb damage. I take it you would like there to end up being less limb damage to the player?
Inwhich case I think just adjusting this game setting "fCombatPlayerLimbDamageMult" Its .5 by default ... so decreasing that should do it.
And looks like you can find and change it easily enough with Fo3-edit under game settings.
Also there is body part data where you can adjust limbs individually ... but I don't know much about that ... the geck wiki should have some info on it though.
For player speed changes , see if the settings mentioned in this thread do what you want https://steamcommunity.com/app/22380/discussions/0/613936673555582637/
On changing NPC health ... looks like you'll have to use the geck. So in the object tree look under "Actors>Creature" for non humans ... then "Actors>NPC" for people.
After you open a window for a particular one ... on the second tab "Stats" is a field for "Health"