How much damage can the Guardian of Faith spell deal?

The guardian of faith spell description states that it disappears after it has dealt a total of 60 points of damage.

There are two things about that which I am questioning:

  1. What about creatures which are vulnerable, resistant or immune to radiant damage? Do you factor in the amount of damage it actually does, or the attempted damage (10 or 20 depending on save)?
  2. What happens if it has done 50 damage after several creatures have gotten close to it (e.g. one saved, two didn’t), and then a creature enters its range and fails the save? Do they take 10 damage or 20 damage?

Does damage to an attribute heal naturally?

Some attacks or spells may cause damage to an Investigator’s attribute score.

For example, in the module Dead Light, the titular creature has an attack:

Consume (fighting maneuver): If it succeeds it melds inside its victim. The victim suffers 1D10+5 CON damage per turn until dead, dying in agony as deathly light pulses from within their flesh and boils from their eyes and mouth, and the their flesh begins to burn and turn to ash (Sanity roll for viewing the Dead Light consume a victim is 1/1D6 loss).

If the investigator somehow survives this attack, will they ever recover the lost CON from this horrible assault?

Are there spells that heal both me and my allies based on the damage dealt to our enemies?

I would like to create a character in D&D 5e similar to World of Warcraft’s Shadow Priest. Specifically one aspect of the Shadow Priest; when he does damage, it heals other players nearby.

I was planning to create a Death Cleric to achieve this and use vampiric touch, but it heals only me. Is there a possibility to link others to me so they would get same amount of healing?

Does hitting a creature with a magical creature counts as magical damage?

Half-Orc Barbarian Conan has been Enlarged, making him Large. During a fight against some Couatls, he managed to grappled one and beat it to death.

Now, having already something (the body of the dead Couatl) in his hands and being a tad affected by its current rage, Conan decides to strike a second Couatl with the first one. Laughs all around the table as the DM rules that he can indeed wield the corpse as an improvised weapon (bludgeoning), given the situation.

A Couatl is immune to non-magical bludgeoning, among other things. But given the fact that the first Couatl is a magical creature and has the Magic Weapons feature, does the damage counts as magical damage?

Magic Weapons: The couatl’s weapon attacks are magical.

If yes, would any “magical creatures” work for this purpose or only ones with the Magic Weapons feature?

How does the Shield Guardian’s damage transfer work when the bearer is immune/resistant to the damage type?

It’s been asked before here what happens when a target is hit with damage a shield guardian is immune to. What about the other way around?

Say a character is immune to a type of damage and takes that damage type (they’re wearing Efreeti Chain armor and take fire damage, for example).

Does the shield guardian take half of the damage and the caster none, or should both characters take none?

Page 197 of the PHB states that resistance and vulnerability are applied after all other damage modifiers.

If the character is resistant rather than immune, does the order of operations change?