1. No, the was needs to be able to make requests to the locally installed bibus logic.
(you even define the lcoal path inside the was as reference)
2. The CM is also a java servlet that requires a java server. By default it comes with tomcat.
I am failing to see the benefit of that configuration.
The ONLY reason NOT to use the FREEWARE and PROVEN STABLE tomcat, is when WAS is IT policy.