Context
I'm doing some theory crafting involving a Shadow Craft Mage - and I'm struggling to wrap my head around just how far I can push the shadow evocation / shadow conjuration spells to maximum effect. I could also use a double check to see if I understand what the saving throws will be for the final effect.
Shadow Evocation
You tap energy from the Plane of Shadow to cast a quasi-real, illusory version of a sorcerer or wizard evocation spell of 4th level or lower. (For a spell with more than one level, use the best one applicable to you.)
Spells that deal damage have normal effects unless an affected creature succeeds on a Will save. Each disbelieving creature takes only one-fifth damage from the attack. If the disbelieved attack has a special effect other than damage, that effect is one-fifth as strong (if applicable) or only 20% likely to occur. If recognized as a shadow evocation, a damaging spell deals only one-fifth (20%) damage. Regardless of the result of the save to disbelieve, an affected creature is also allowed any save (or spell resistance) that the spell being simulated allows, but the save DC is set according to shadow evocation’s level (5th) rather than the spell’s normal level.
Nondamaging effects have normal effects except against those who disbelieve them. Against disbelievers, they have no effect.
Objects automatically succeed on their Will saves against this spell.
Questions:
Can I use Shadow Evocation to cast a Meta Magicked version of Flaming Sphere (2nd level) that has been empowered (Requiring a 4th level spell slot but still counts as a 2nd level spell)?
Do I have to already know or possess the relevant meta magic feat to mimic this spell combination?
If I can cast the spell in this way - what are the target saving throws? Is the saving throw for a 5th level spell for disbelief then a saving throw against a 2nd level spell for the flaming sphere affect?
I'm not sure if doing virtual metamagic would "overide" the shadow evocations set save DC's.
If all of that is possible (The broken part): Could one use the Meta Magic: Sanctum Spell on the mimicked evocation to lower a 5th level spell to 4th level to be a valid target for Shadow Evocation? Assuming of course we are not inside our sanctum.
Sanctum Spell [Metamagic]
A sanctum spell has an effective spell level 1 higher than its normal level if cast in your sanctum (see below), but if not cast in the sanctum, the spell has an effective spell level 1 lower than normal. All effects dependent on spell level (including save DCs) are calculated according to the adjusted level. A sanctum spell uses a spell slot of the spell's normal level.