I exported out an obj sequence and my objs polygon normals are all soft shadowed upon re-importing into maya, modo, and max. Is there a way to export out the polygon meshes with hardened or preserved normals?

Try using the Facet SOP and turning on Cusp Normals. This cusps the vertex normals, not the point normals. I'm not sure how Maya will interpret this, but it's worth a try!

If I understand correctly Facet SOP has cusp polygons feature and not cusp normal. It does harden edges but makes unique points for every face (try to display point numbers). “N” attribute only appears after post(or pre)compute normals is on.
Vertex SOP>Keep Normal(Cusp Normal) changes vertex normal attr. by angle as you would expect.
For the initial question I tried to export obj from Houdini to Modo and it seems that Surface Normal map(in modo terms) doesn't exist in obj file. But with alembic N goes to Surface Normal. Hope it helps.

Great! Vertex SOP worked perfect

Thanks a ton!!!! )

You're welcome.
I'm not sure why, but it seems that houdini just don't export normal information in .obj files at all. May be a bug?!