Can a wizard with cleric levels scribe wizard spells he had prepared from the cleric class in his spellbook?

There’s been a debate on a D&D discord server that’s caused me a lot of trouble. Here is the question: if a wizard 2/cleric 2 has a wizard spell prepared from being a cleric, rather than from being a wizard, then should the wizard-cleric not be able to then scribe that spell into their spellbook the same as if they had it prepared from anywhere else?

Edit: This is different to the bard/wizard question due to bards having spells known, and clerics preparing spells just as wizards do.

Can a warlock scribe a scroll from their ritual book? [on hold]

Say I’m a warlock with Detect Magic in my tome as a ritual spell. I otherwise don’t know Detect Magic.

Can I make a scroll of Detect Magic? I’m pretty sure the answer is no, since a ritual spell in my book doesn’t count as a spell known, but it feels a little strange since I can cast the spell as much as I want (albeit as a ritual).

If a cleric takes the Ritual Caster feat and picks the wizard list, are they able to scribe rituals that are on both classes’ spell lists?

I am playing a cleric. I would like to take the Ritual Caster feat at level 4 to access some wizard spells for utility.

Can my cleric spend the material cost to add rituals shared by both classes (like Detect Magic, Detect Poison, Identify, Gentle Repose, etc.) to the ritual book? Or do I need to find a wizard based written source?

Are there any other prestige classes for 5e besides the Rune Scribe?

In the Unearthed Arcana article “Prestige Classes and Rune Magic”, they introduce the idea of prestige classes, a class with only a few levels and more multiclassing prerequisites, borrowed from earlier editions (I remember them from 3.5e, but only via NWN2 rather than the real game).

In the same article, they give the Rune Scribe prestige class as an example. Excluding random homebrew, have there been any other prestige classes for 5e? Since prestige classes were only ever a UA thing, I imagine other UA articles are the only places they would likely have been released, but I was unable to find anything going through them myself. But there may have been some other semi-official source I am unaware of…

Can Nystul’s Magic Aura mask a creature created by a Protean Scribe?

I play a Protean Scribe (Mythical Classes) and it has word powers. You can write a story so eloquent that you can bring the very creatures and objects of your story into existence.

In either case, the storied creature or object is obviously magical, radiating dim light in a 5 ft radius. An object or creature remains until it is reduced to 0 hit points, you choose to erase the story, or until you take a short or long rest.

If I cast Nystul’s magic aura, can I prevent the creature radiating dim light in a 5-foot radius? Does this spell mask this effect?