>>8629532Arms are exactly the same, so Fused Zamasu's hands fit no problem. The one potential issue is that Fused and Regular Zamasu have slightly different shades of green for their skin tone, with Fused's skin tone being a bit darker. Not a huge difference, but it's there.
Here in this pic, the right hand (figure's right) is Fused's hand while the left is Regular. Sorry, I know it's probably tough to tell from my pic.
>>8629700Fused could use the sword with the flat palm hands and regular Zamasu has the exact same flat palm hands as Fused (minus the ring), so should work no problem.