inifistto be fair their headphones are extremely easy to mod to detachable, I've done flush fitting disconnect mods to all my wired headphones, except that one cause it was expensive AF.
def3nestrat0rjack? buy neutrik
sockets? honestly whatever so long as they're straight-style, and I'd do 2.5mm because 3.5mm doesn't fit the chassis of the Ad-hundredX series. Cable I use mogami, you gotta strip it and use the cores, braid in paracord and use heatshrink for nice ends. Really darn easy all around.
Xerclifit's a dual entry headphone so making it balanced is easy and only requires you using 1 extra wire and wiring it to a balanced plug instead of a 6.5. So yes.
Also, looking at some cables people are getting away with selling for 80 to 200 dollars I can see some of them literally put less than 20 minutes of effort into making these, but people will buy them (cause they're dumb).
I fully braid every part which takes longer but ends up in cables looking a lot nicer.