not sure I can explain baking (properly)  but here goes ;-) you apply a set of textures to a model in (this case blender) then you can "copy"[bake] those textures to a uv map, can be a completely new map or the one your using to "bake" from, can bake normals (makes a low poly thing look high poly) can bake any pass you can think of (displacement, specular etc)

can use as many uv maps as you want for setting it all up, eg you could get a v4 skin tex to fit aiko can add sss. dirty vertex AO anything!! then "bake" it to the Aiko uv map

dont get me wrong its NOT a click click thing it takes time and bloody hard work ;-) but the results can be awesome

is lots of tuts on utube, look for baking, projection painting is lots of great tuts and a few not so helpfull ;-)

{note ; while I know these things are possible is some I aint done yet ;-) RL gets in the way lol }

quick tip # poser does this really good subD at render time so if you bake a displacement map crank up the subD in blender BUT export the low poly (subD under 2 )