Are procedural textures lower in RAM consumption then bitmap textures and do they calculate faster?
Procedurals require much less mem than bitmap textures, but they might render slower depending on how complex your rendertree is.
Is there a way to display how much RAM the scene uses? (Besides ctrl+alt+delete)
Do you think it's a good idea to use procedural textures for background elements?
I don't see why not - just be aware of any possible flickering in animation due to tiny detail in the texture. Can be easily fixed in the rendertree though.
Can you build a decent character animation that fits into 1 to 2 GB RAM?