Basic 235 body with viewfinder weighs 3.5 kg or 7.7 lbs, add IVS and handgrip you're up to 4.1 kg or about 9 lbs.
35mm neg is a bit over 2g per ft so 400 ft plus core is maybe 850g or a bit under 2 lbs.
An older 35-3 or 435 400 ft mag is about 1.7 kg or 3.7 lbs, 400ft displacement mags for steadicam are about the same. I can't find specs on the lightweight shoulder 400 ft mags but I would estimate they would be maybe 2.5 to 3 lbs.
So you're probably looking at 14 to 15 lbs for a 235 with IVS and a fully loaded 400 ft mag.
A typical standard-speed cine prime (say Ultra Prime or Cooke S4) adds another 3.5 to 4.5 lbs.