"3. Is a project more/less likely to succeed if the many (Dev/Deploy) roles on a project are actually filled by different people as recommended in SCEA?
J2EE Product Provider
Tool Provider
Application Component Provider
Enterprise Bean Developer
Web Component Developer
Application Client Developer
Application Assembler
Application Deployer
Application Administrator "
In real world scenario, its very rare that EACH of the above mentioned jobs are done by different people. Generally, all the developement (EJB's, Clients, etc) , assembling and sometimes even deploying can be done by the Developer.
Administration can be done by a different person as opposed to the developer doing it as administration needs more in-depth understanding ...