I think I found the problem.
It's because of the integration of chaos and field model mods.
I realized that Max dood was using the old 7th heaven, and his weapon models were vanilla.
Apparently, when you use the new integrated field models mod in 7th heaven 2.0,
if you set a weapon's dynamic weapon option to 'no change', it doesn't show the vanilla model, but rather erase the sword on Cloud's back, essentially the same as not using the dynamic weapons mod.
I don't know if this is only happening to me, but it seems to be the case.
I searched, downloaded and imported the old chaos mod(because it doesn't show in the 2.0 catalog anymore) manually,
and now it shows the texture of the sword rather than just a white colored model of it.
But the vanilla buster sword still overlaps with the sword I equipped(the force stealer at the moment).
I guess if I get the old field model mod, I'll be able to solve the problem.
I'll try this when I get the time to do so.