There seems to be an easier way to arrive at this outcome. ([But] I'm [not] a luthier, baby, so why don't you skill me...)
Willie, its actually pretty simple. When someone designs a new guitar the first thing they pick is the scale length. That is one of the most important things affecting playability. Scale sets the amount of tension in the strings for a given tuning, has a lot to do with the mix of fundamentals and partials (ie how it sounds). Once you've selected a scale you decide where the neck to body join is going to be - it might be the 14th or 16th or 18th fret. Again, a bunch of factors come into play. With those two measurements everything else falls in place - bridge location, pickups, yadda yadda yadda.
A long time ago Leo Fender selected 25.5 inch for his scale length (it was a popular one with classical guitar builders) and put the body joint at the 16th fret, or 15.380 from the nut. That means the uncompensated location of the bridge is 10.120 inches from the body joint. All is well because both the neck and body are built to those dimentions.
Advid want to put a 24 inch scale neck on a body that has the bridge located for a 25.5. It ain't gonna work. Well, actually it can be made to work by moving things all around. It makes no sense to do that with an existing body and neck, it makes a lot of sense to do it from scratch. The Jaguar/Mustang guitar does have a 24 inch scale, the joint is at the 17th fret (more or less) and the bridge is in the correct location for that guitar. Advids simplest option is to buy or build a parts jagstang with tele pups and bridge and whatever else he wants.
A kind of interesting option is that if you put a capo on a 25.5 inch guitar at the first fret you basically have a 24 inch scale (its a hair more). That opens the idea that if Advid took a standard tele and simply wacked off the neck at the first fret and moved the head back and reconnected it.... You won't find too many luthiers who would do that, but I would certainly make a shorter neck with a fretboard that had been shortened. Its even possible that someone sells such a board.
So, bottom line, changing the scale on an existing guitar is possible but a nightmare, building one from scratch to Advid's specifications is very doable.