Can you cast Magic Stone on 3 pebbles as a bonus action, throw a stone as an action, then, on your next turn, throw the 2 remaining pebbles?

Question

Can you cast Magic Stone on 3 pebbles as a bonus action, throw a stone as an action, and then on your next turn, throw the 2 remaining pebbles?
That is, throwing the first pebble as your action and the second as your bonus action, using the Two-Weapon Fighting rules (PHB pg. 195; emphasis mine)

When you take the Attack action and attack with a light melee weapon that
you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand. You don't add your ability modifier to the damage of the bonus attack, unless that modifier is negative.

If either weapon has the thrown property, you can throw the weapon, instead of making a melee attack with it.

"My Reasoning" for the question:

I know that an attack is an' action. The issue is, if after throwing 1 (assuming you used that turns bonus action to cast magic stone), on your next turn could you dual wield the remaining 2 stones and throw both? (per the general two weapon fighting rule from chapter 9)
Carrying on:

Seeing as there is no, individual, entry for "pebble" and/or "stone" (making it an improvised melee weapon?) & it's 100% considered "thrown" (or used as sling ammo):

Could the magic stones also be assumed to be "light" (like a dagger, light hammer or handaxe is?

Seeing the limited use of bonus action's spells when attacking ranged as a Druid: Magic Stone, Shillelagh, and Healing Word, as options. None are "direct attacks".

Especially before level 5, when Produce Flame and Create Bonfire outpace Magic Stone as ranged attack options, being able to "dual-wield" 2 Magic Stones would be a doubling of potential damage output at range, mainly for druids levels 1 to 4.

(Side note: I have melee handled, dual-wielding a Shillelagh'ed club with an off hand scimitar. It's pre-level 5 ranged options I hope to expand.)

Answer 1

No, Two-Weapon Fighting does not apply.

Magic stone is neither a weapon, nor melee, nor light.

Two weapon fighting requires that you be using a light melee weapon. Melee weapons can be used to make melee weapon attacks.

The magic stone spell creates objects with which you can make a ranged spell attack only. This spell attack uses your spellcasting modifiers for attack and damage, regardless of who is using the stone. This spell attack does not add to the pebbles' normal damage (like magic weapon or hex or smite) but replaces it completely. This indicates that the attack used in magic stone is not based on any weapon-like properties, so you would be at a stretch to classify the magic stones as weapons. If they are not weapons, they cannot qualify for two weapon fighting.

There is still a bit of grey area, though. In principle a regular pebble can be used as an improvised weapon, so it is possible to argue that magic stones are weapons too. However, because magic stones can make only ranged attacks and not melee attacks, they are at best ranged weapons, not melee weapons. (The dart and net are ranged weapons which also have the thrown property. This means that being thrown does not imply being a melee weapon.)

Because the magic stones are (at best) ranged weapons and not melee weapons, they cannot be used with two weapon fighting, even if you could argue that they were light.

But I shall also argue why magic stones (and pebbles generically) are probably not light weapons either. From PHB 147,

A light weapon is small and easy to handle, making it ideal for use when fighting with two weapons.

The definition of a light weapon makes no reference to a weapon's weight. A critical part of being 'light' is being "easy to handle", such that it is ideal for use when two-weapon fighting. Rapiers and warhammers are 2 lb. and are not 'light'. A dart, which is the closest listed weapon to a thrown stone, is only 1/4 lb. and is also not 'light'. Because a dart is not 'light', I see no reason to assume that a magic stone is 'light' either.

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You are asking this question because you wish to get more damage at a range. Consider that ranged combat already comes with significant advantages, namely you get to stay out of reach of people with melee attacks. The higher damage potential (from two weapon fighting, opportunity attacks, and availability of stronger weapons) is the primary benefit of melee. If you remove this advantage from melee, the reasons for using melee become fewer and balance suffers. Choosing ranged over melee is a trade-off.

If you want to optimise your damage output from magic stone, get two or three friends (or hirelings or familiars or conjured creatures) to help you throw the stones. By using allies, you can get three attacks every turn from magic stone, which is twice as fast as your proposed scheme of three attacks over two turns.