I'll try to answer all your question. 1) Is it possible to have both the remote & local component interfaces to a Bean( EB/SFSB/SLSB)in the same ejb-jar? If so how to define them in DD.
Yes, you can. Here's an example.
2) Can CMP fields of EB be primitive?
Yes, this is from the EJB 2.0 specs. The Bean Provider must ensure that the Java types assigned to the cmp-fields are restricted to the following: Java primitive types and Java serializable types.
3) Should EB in EJB 2.0 be CMP & CMT only?
No, an EB can be CMP or BMT (Bean-Managed Transaction)
When designing an enterprise bean, the Bean Provider must decide whether the enterprise bean will demarcate transactions programmatically in the business methods (bean-managed transaction demarcation), or whether the transaction demarcation is to be performed by the Container based on the transaction attributes in the deployment descriptor (container-managed transaction demarcation).