Can you conjure evard's in mid-air? Hmm... Conjuration says this:
A creature or object brought into being or transported to your location by a conjuration spell cannot appear inside another creature or object, nor can it appear floating in an empty space. It must arrive in an open location on a surface capable of supporting it.
I'm not sure that a field of rubbery tentacles counts as an object or creature, though...
Edit: I guess it doesn't break anything... so we'll roll with it.
But... there are more problems with your plan... Copied from the encounter thread:
Raoul can't see Ris-Janna, and has no way of knowing where she is. She is outside the telepathy range, he never knew where she was to start with after DDing away, and even if he did, she's moved...
He also doesn't know where the flying dude is, but he can try to figure that out from the sound of the winds whipping around him (with a Listen check). If he manages to center an Evard's on him, he'll definitely get RJ with it, though.
Listen DC to pinpoint the whirlwind around the unseen flying dude's position is: 34 (we'll say it starts at -20, for the windstorm, +30 for distance, +20 to pinpoint, +4 due to the storm)
To get within 20 feet of him for spell targeting, we'll reduce the DC by 20 (ad hoc), for a total of 14.
To know R-J is fighting him there, the DC would be 24, using the same factors, but starting with a -10 DC for combat.