All of the fields in your schema have
required="true".
You're telling Solr that the results from each entity need to have ALL of the eid, ename, pid, pname, entity, and singlekey fields.
Employee doesn't have a pid or pname field, so pid and pname shouldn't be required. In the same sense, Product doesn't have a eid or ename field, so eid and ename shouldn't be required.
Removing
required="true".
from pid, pname, eid, and ename will allow you to index.