When there are some skill checks, does the system pick the highest value among all characters in the party, or it depends on who is interacting with something?

For example, when buying something from a merchant, does the price depend on Bargain and Persuasion skill of the character who is talking to the merchant, or it picks the highest in the party?

Also, I put a few points into that skill, but I don't see prices in the shops changing, even though it says it should give more favorable prices. Does it only affect it at certain levels of the skill or the effect is just so small that it's not reflected in the numbers yet?

As I remember, there were rumors about implementing player strongholds (with upgrades).
But I didnt find any stronghold possibility, at least for fighter/thief class.
Are They implemented at all?

How do you direct certain spells to a specific target?

For example Siracca just joined my party and during a fight I tried to cast Armor of Alnarius on another character, but she cast it on herself. Or that spell only works on the caster?

UPDATE:

I got it, I think it's only intended for the caster.

Do natural resources like mushrooms and etc. grow back after they are harvested?

I have pretty hard time finding some ingredients like Redcomb for example. So making potions and etc. so far is barely possible.

When investing points for example in weapon skill, the table in the UI shows total value (taking in account attributes and etc).

When that value reaches 100% it's not growing anymore (I suppose that's the chance of hitting?). Is there a benefit in investing more points then?

I see, thanks. That makes finding resources a bit hard.

A related question, do merchants restock their items? For instance it would be good to be able to buy more arrows for party archers, since they eventually run out (especially higher quality ones). Thanks. I was going through the manual and found this detail:

The formula for bonus damage is:
Damage Attempted = Base_damage + ((Phy – 7 + WepSkillPoints) / 4)

Does it mean that Damage Attempted will grow with higher weapon skill points, i.e.even when the chances are capped at 100% like above? So there is some benefit in investing more points in specialized skill even after that?

UPDATE:

I confirmed it does help a bit - you can see total damage going up in that case in character stats when opening inventory.