Garage air unit?
Name Withheld: That is a quality installation
That is a quality installation: a modern, high-efficiency HVAC unit with well-designed ductwork covered in safe insulation with a reflective foil covering (a cheaper installation would have smaller ducts and no insulation). Nothing to worry about there.
the insulation is yellow fibreglass batting a half inch I think it looks well sealed,a few spots might do with some good quality duck tape, dollar store duck tape,,passemon by the stuff falls & peels off after a week, visit the hardware guy at a remodlers big everything store, ask for good quality ducktape
you're fine. but do NOT walk on the ducting -- it can't support a person's weight
You need to join the Navy and serve a tour on an aircraft carrier. Miles of insulation on the ship. Unless you are removing (or installing) the ducts, there is no harm. If there is a big tear or damage on the ducts, stay away from his house.
Not unless you bust open the duct. The insulation is harmless. The most that contacting it would do is make you itchy where it touched your skin. If you do get it on you wash the area with cold or slightly warm water. Nothing to worry about.
It isn't a rattlesnake, it isn't going to attack you.