There are two types of hosts because the technology improved over time, at least partially to increase cost efficiency. Thy are referred to as generation one and generation two. It seems that either generation can contain a bicameral mind.
Generation one hosts seen in Logan and William’s time in the park. If you cut them open or dismember them, you can see robotic parts and wires. Dolores is the prototype generation one host, and in episode one, Stubbs tells a female tech that Dolores is the oldest host in the park. In the schematic illustration, you can see machine parts in the diagram. In the present day, Bernard discovers the generation one family living in the remote house. Young Robert is, evidently, also some kind of prototype.
Generation two hosts are the flesh and blood version, rendered on the loop, in the present day timeline when The Man in Black has returned. In the “Bernard” schematic, we see muscles and organs instead of machine parts. Felix tells Maeve that second generation hosts are nearly the same as humans. They’re also close enough to us to be susceptible to the same ailments we are. In one scene, Felix and Sylvester clean MRSA out of Maeve’s abdomen.
In one scene, a host is shown coloring in, sanguination.