spellcasting specialization and multiple spells, When casting more than one spell at the same time, how do this work? Options

[telechus]

So if I specialize in Detection spells and have a Mentor Spirit that provides a bonus to Manipulation spells, how do these scenarios work out:

1) I cast Levitate on myself and someone else at the same time. Do I get 2 extra dice for each casting, or just 2 extra dice for the entire pool?

2) I cast Armor and Analyze Device at the same time. Do I get 2 extra dice for each casting, or just 2 extra dice for the entire pool?

3) For the bonus from a Mentor Spirit, it applies only to casting the spell, not countering or drain?

I'm using SR4A and Street Magic. Thanks for your help.