Yes, I'm far from presuming this was an attempt to simply stalk Jayme.
If you have a "long, careful plan" to kidnap someone, why create an unnecessary double homicide scene, leaving ballistics evidence, etc.?
Barron is a super-safe place, i.e. vulnerable. He could have kidnapped Jayme in so many alternate locations that would have NOT involved murder.
Shotgun to the front door sounds awfully rage-y to me. And what the heck strategy includes shooting blindly through the house door if he's trying to take Jayme alive? How did he know he wouldn't hit her?