In a a description of lingering spell it says "Instantaneous area effect spell lasts for 1 round" Would this allow lingering evocations work on it since it is not instant any more?
It does look that way - is there any Evocation spell that's going to cause trouble with this combo?
Well putting a fireball in and when the enemies rush out of it and putting them back in it could be trouble.
It could also bottleneck enemies a lot easier with burning hands and fireballs lining the battlefield