Can the Command spell be used to force someone to drink poison?

The Command spell does the following:

You speak a one-word command to a creature you can see within range. The target must succeed on a Wisdom saving throw or follow the command on its next turn. The spell has no Effect if the target is Undead, if it doesn’t understand your language, or if your command is directly harmful to it.

Can the Command spell be used in combat to force a foe to drink poison?

Presumably, the caster would hold out a vial of poison when giving the order.

Is the Adult Gold Dragon’s Weakening Breath considered a curse, disease, or poison?

In a fight with an Adult Gold Dragon today our delightful barbarian suffered from the effect of Weakening Breath. Our transmutation wizard used his Transmuter’s Stone for Panacea to restore hit points, and cure poison, disease, and curses. Would this cure the effect of Weakened Breath?

Does a character hit with Drow Poison always have to attempt the 2nd Fortitude Save?

The description of Drow in the SRD states:

An opponent hit by a drow’s poisoned weapon must succeed on a DC 13 Fortitude save or fall unconscious. After 1 minute, the subject must succeed on another DC 13 Fortitude save or remain unconscious for 2d4 hours.

Does the character have to make the second saving throw if they succeeded in the first save? The inclusion of the word “remains” suggests that the character was already unconscious, which suggests that this second saving throw is only required if the first one was failed.

However the rules for poisons suggest that the second saving throw is “usually” required even if the first succeeded. But it talks about additional “damage” which unconsciousness isn’t, exactly:

When a character takes damage from an attack with a poisoned weapon, touches an item smeared with contact poison, consumes poisoned food or drink, or is otherwise poisoned, he must make a Fortitude saving throw. If he fails, he takes the poison’s initial damage (usually ability damage). Even if he succeeds, he typically faces more damage 1 minute later, which he can also avoid with a successful Fortitude saving throw

So…

If a character succeeds in their initial saving throw against Drow poison, are they still required to make another save a minute later?

Is Poison consumed by the first attack?

Is a vial of Poison consumed by the first attack of such a weapon or I get the +1d4 Poison damage for each attack I do in one minute?

Poison, Basic. You can use the poison in this vial to coat one slashing or piercing weapon or up to three pieces of Ammunition. Applying the poison takes an action. A creature hit by the Poisoned weapon or Ammunition must make a DC 10 Constitution saving throw or take 1d4 poison damage. Once applied, the poison retains potency for 1 minute before drying. (PHB, p. 153)

Rule as written I would say it would last for the full minute, unless there is another part i missed where it states otherwise?

Similarly, for Injury Poisons (DMG, p. 257), how long does the effect on the weapon last? (For example for Serpent Venom (Injury)).

Harvesting Poison from a familiar

Crafting and Harvesting Poison (p258 of the DMG) Says that a creature must be dead or incapacitated before you can make a DC 20 nature or Poison kit check to get a single dose of poison.

However, It seems to me that this system is for collecting the venom of random encountered creatures. If I have a snake familiar, could I not just command the familiar to bite a jar with a thin leather membrane to collect the venom? Would there still be a need to incapacitate the snake or make a check?

Number of saves vs lingering clouds of poison doses

If someone were to use either the toxic censer or alchemical wax to create long duration clouds of poison, how many times do creatures within those clouds have to save against the poison dose?

Are they affected once and never again by the same cloud, meaning there’s no difference if they are in it for 6 seconds vs the full 5 minutes or full 1.5-2.5 hours for the wax?

Or would they have to resave against the poison each turn, potentially rapidly increasing the DC and duration of the poison to ridiculous amounts for a single dose? (+2 DC and 50% duration each application)

Would a Periapt of Proof Against Poison nullify the effects of alcohol?

The description of the Periapt of Proof Against Poison (PoPAP) says that “poisons have no effect on you. You are immune to the poisoned condition and have immunity to poison damage.”

So I’m wondering if a character could get drunk while wearing a PoPAP? There’s no “drunk” status condition in D&D 5e, but drunkenness is caused because you’ve consumed enough alcohol to poison yourself, however slightly. Also, does the wearer of the PoPAP know they’ve been poisoned? Like for instance, if someone put spider venom in their food, would they know the food was poisoned when they ate it?