Forget glue, just make sure you get enough of the stuff you use on the exposed part of the handle onto the tapered part that'll be inside the 'hook....
Prolly not a Good Idea. Just adds weight, everything underneath is already suspect, you're just spending money & labor on top of an 'iffy' base layer...
No, taping is neither necessary nor recommended. Those rubber bits aren't o-rings exactly (unless your product has a proprietary design) they're more...
I'd have to believe that once dilbit reaches a refinery that the liquifying NG is recaptured /used in the refining process or 'refined' into another...
Watching that YT clip, first thing came to my mind: they're actors fer crisakes, they're not really doin' that, too risky! Bet there's a vetted crew...