1. Ectoplasmic Spell - does it work in the reverse, can a pc that casts ethereal jaunt use this to affect creatures on the material plane?
Technically, no it does not go both ways.
2. Intesified Spell - Does the caster level limit increase by 5 or the amount of dice rolled. Ex. fireball increases to 15d6 with a CL of 15 since it goes up 1 for 1. Now does the same level pc who casts magic missle max out at 10d4 or 7d4 (since 5 more levels technically equates to 2 extra dice)?
I thought of the same thing. Unfortunately, no, it works specifically on the damage dice. Magic Missile does not deal more dice of damage as your CL increases, it only shoots more missiles. Yes, that distinction matters. So, you can't Intensify Magic Missile--or, well, you could, but it would have no effect.
1. Ectoplasmic Spell - does it work in the reverse, can a pc that casts ethereal jaunt use this to affect creatures on the material plane?
2. Intesified Spell - Does the caster level limit increase by 5 or the amount of dice rolled. Ex. fireball increases to 15d6 with a CL of 15 since it goes up 1 for 1. Now does the same level pc who casts magic missle max out at 10d4 or 7d4 (since 5 more levels technically equates to 2 extra dice)?
1. I do not believe so, as nothing in the feat description or the spell description seems to support that notion.
2. Intensified spell cannot be applied to magic missile at all as its dice of damage is not based on level, only its number of bolts.