well from what i understand in terms of what warframes are physically made of, theyre basically super advanced cyborgs.
start with a normal fleshy organic human base, and add infested spores (aka literal nanobots) to physically reconfigure their body at the cellular level to add the metal aspect, add the circuitry that enables them to be programmed for shields, ui overlays, transferrence and other such things...
so the way i figure prettymuch all warframes would have fairly comparible material properties as the organic fleshy cellular base they started with, just a bit stiffer than usual since every cell now also has a microscopic layer of metal to it, but still has a very much cellular structure.
so not full on liquid goop like the T2 Terminator, but not completely rigid Robocop either. just... mm. i guess the android girl from automata? like... that kinda texture. flesh+