Who can use a Spell Scroll scribed by a bard who learned the spell using the Magical Secrets feature, if it is not normally on the bard spell list?

Question

When a bard learns a spell using the Magical Secrets feature, it counts as a bard spell. Of note, should they replace any spell learned via Magical Secrets at a later level, they can only replace it with one from the bard spell list. Rules designer Jeremy Crawford actually did make a ruling on Twitter regarding this, so this is clear: replacing one's Magical Secrets spell is easily done - it is just somewhat unwise to do so.

Say a bard picks find familiar as a spell. Massive boon! For dirt cheap, they can print them off as spell scrolls. Now, who can use that spell scroll?

I see three possibilities:

1. This is a wizard spell on the wizard list - designed for wizards. Clearly only a wizard can use a wizard spell on the wizard list designed specifically for wizarding ways, right? So obvious: a wizard buying this spell can transcribe it into their book (with a good roll on a good day) - or simply use it and get themselves a familiar.

2. Any Magical Secrets spell, no matter which spell list it once came from, counts as a bard spell for all intents and purposes (i.e. "learning, casting and recording"). Should a bard make such a spell scroll, any other bard can use it. A "secret" no longer! But to be clear, if it is a bard spell, only bards could use this magic item. A wizard would not ever figure it out. A druid would have no chance. A barbarian would accidentally use this scroll as a fire-starter.

3. You can use any scroll if the spell is on your class list. So almost anyone can use that charm person scroll. Thus, the bard scribing such a spell scroll cannot even use it themselves. Imagine the ignominy with scribing any spell from Magical Secrets: "I cannot read any of what I just wrote down."

Which interpretation is correct?

(I did search to check whether this was a repeat of a previous question before posting.)

Answer 1

Spell scrolls don't care who created them.

The rules for using spell scrolls say:

If the spell is on your class’s spell list, you can read the scroll and cast its spell without providing any material components.

The scroll doesn't care about the class of its creator. The only requirement is that the particular spell appears on your class's spell list.

Magical Secrets spells count as Bard spells.

As for your situation where the Bard has a scroll bearing one of their Magical Secrets spells, the Magical Secrets feature description has this to say:

The chosen spells count as bard spells for you.

So a Bard would be able to use a spell scroll bearing one of their spells learned through Magical Secrets. That is, if Jimmy Page (a bard) learns haste through Magical Secrets, he can use a haste spell scroll created by anyone, no matter their class. But if Jimmy Page learns haste through Magical Secrets and creates a haste spell scroll, Robert Plant (another bard) can only use the haste spell scroll if he also learns haste with Magical Secrets.