Jesse's age is revealed when the doctor who saved Gus after the Cartel attack says he's "25, smoker and drinker" and also says his blood type.
The electronic pulse in the last scene is the sound of the invisible Id monster's footfalls from Forbidden Planet (1956).
Hank mentions a buddy from Glynco. This refers to The Federal Law Enforcement Training Center (FLETC) located just NW of Brunswick, GA.
The amount Skyler gave Ted via a fake inheritance was $621,552.33, but the amount he owed to the IRS was only $617,226.31; meaning she gave him an extra $4,326.02.