Are resin fillings less likely to be painful and sensitive to heat & cold than silver amalgam?

No: If they are done properly, sealed well they should be fine. If its deep silver or composite would possibly irritate.

No: If its sealed well it should be fine, if they are deep cavities composite or silver may cause irritation , sensitivity.

White , gold , silve: White fillings called composite, amalgam or silver, gold , or ceramic ( porcelain).