Absolutely not, any 3d object that has been UV unwrapped will work fine with these effects.
TIP : All primitive objects like cube, sphere, and even Suzanne come pre-unwrapped by default. :)
No, they work from the 'Shader Editor' window only.
No, literally any decent machine can run these effects.
They worked flawlessly on my 8-year-old potato laptop!
Yes, these effects use UV coordinates as their base.
Both, Cycles and Eevee are supported.