Can a simulacrum be healed by any means other the ‘complex process’ outlined in the spell?

Inspired by another discussion of Simulacra – can a simulacrum actually heal via any method other than the ‘complex process’ outlined in the spell? Or is that process simply another option? What if the copied creature type has Fast Healing, or Regeneration? Do Cure Wounds spells function on the simulacra? Is the simulacrum actually even a creature?

Is the amount healed for multiple-target healing spells rolled per person or once for all of them?

Take for instance, the spell Prayer of Healing (in the online Basic Rules):

Up to six creatures of your choice that you can see within range each regain hit points equal to 2d8 + your spellcasting ability modifier. This spell has no effect on undead or constructs.

The “Damage Rolls” rule says that “If a spell or other effect deals damage to more than one target at the same time, roll the damage once for all of them.” Does that same principle apply to “Healing Rolls”?

That is, if I target my whole party with a spell like this, is it a separate 2d8+modifier that gets rolled independently for each target, or do I just roll the once and that same amount is what each target gains?

Obviously the game “works” either way, and playing it however one’s table finds most fun is great. But, I’m looking for official sources or references if available. If there aren’t any, then I would accept any semi-official or well-informed well-reasoned arguments, preferably backed up by evidence that it’s the usual way that groups handle this.

Can you take actions after being healed at 0hp?

Suppose the case: There are three participants fighting, a Fighter, a Cleric and a goblin, the Fighter and the Cleric fight against the goblin. The initivative is Fighter (18), Cleric (12) and goblin (1).

So, in the first round:

  • The Fighter attacks the goblin and misses

  • The Cleric attacks the goblin and misses

  • The goblin attacks the Fighter and puts it down no 0hp

In the second round:

  • The Fighter makes the death saving throw, and passes it

  • The Cleric heals the Fighter

And at this point I don’t know if the Fighter can take any actions during this turn, or has to wait till another round starts, so the rest of round 2 could be:

  1. The Fighter attacks. The goblin attacks. Round 3 starts.

Or:

  1. The goblin attacks. Round 3 starts.

So, does the Fighter get to take any actions during round 2?

Can you be healed or stabilized (if downed) while petrified?

I just posted this question about whether you continue making death saving throws while petrified if you are at 0 HP. The answer was yes. But I thought of another question:

If you are downed and petrified, you must still make death saving throws. Can you receive healing or Medicine checks in order to stabilize you (so you stop making death saving throws) while in this condition?

In addition, if you survive, are you able to recover hit points either by healing magic (from other PC), potions, taking a long rest, or spending hit dice on a short rest? I mean, are you able to recover hit points by any source of healing while petrified?