Corrupt/Sanctified Spell and Versatile Spellcaster

[ATHATH]

So, let's say that I'm a Wizard, and I (through one of the many ways to do so) acquired Versatile Spellcaster. Can I sacrifice two of my 6th level slots to cast Death by Thorns?

If I'm a Spontaneous caster, and take Magical Training (Wizard) and Versatile Spellcaster, can I A: learn new spells in the list granted by Magical Training (via the standard method of adding spells to your spellbook), and B: cast those spells with Versatile Spellcaster?

[Crake]

So, let's say that I'm a Wizard, and I (through one of the many ways to do so) acquired Versatile Spellcaster. Can I sacrifice two of my 6th level slots to cast Death by Thorns?

If I'm a Spontaneous caster, and take Magical Training (Wizard) and Versatile Spellcaster, can I A: learn new spells in the list granted by Magical Training (via the standard method of adding spells to your spellbook), and B: cast those spells with Versatile Spellcaster?

It depends on how hard you squint

But more seriously, by RAW, yes, versatile spellcaster on a wizard lets them sacrifice 2 spell slots to cast any spell in their spellbook of one level higher, due to the fact that a wizard's "known" spells are defined as "any spell in his spellbook". Note that wizards still actually need to have corrupt/sanctified spells in their spellbooks to prepare/know/cast them, unlike most prepared divine casters (read: all of them except the archivist) who can prepare any spell available to them as they wish, but do not actually count as knowing them.

The second issue is a bit less clear, because you are not actually a wizard. Magical training allows you to cast the three spells you pick specifically, as either a wizard or sorcerer, so while you would be able to (arguably) add spells into your spellbook, you would not actually be able to cast them until you got an actual level in wizard, because only a wizard actually counts as knowing all the spells in his spellbook.

[ATHATH]

Ah, darn. Can I take a level in Mystic Theurge or something to gain an effective level of Wizard?

[Flickerdart]

Ah, darn. Can I take a level in Mystic Theurge or something to gain an effective level of Wizard?
No. Mystic Theurge only progresses an existing class. If your casting is not from a class, tough.