I am considering ordering these sleeved PSU cables from corsair to tidy up my case. Will they work with my non-corsair, Seasonic PSU? Even though they seem like a fairly non-proprietary kind of cable, the corsair website only lists corsair PSUs as compatible.
I dont know specifically to your case, but in general you cannot mix cable brands. Often even the same brand will require different cables for different models.
Hence when you lose modular cables, you must contact your company for specific replacements, as opposed to giving you general cables. Each brand is different, which makes it just risky swapping cables.