Best Practices for FSCM Multiple systems scenario

Hi guys,

We have a scenario to implement FSCM credit, collections and dispute management solution for our landscape comprising the following:

1. a 4.6c system
2. a 4.7 system
3. an ECC 5 system
4. 2 ECC6 systems

I have documented my design, but would like to double check and rob minds with colleagues regarding the following areas/questions.

1. Business partner replication and synchronization: what is the best practice for the initial replication of customers in each of the different systems to business partners in the FSCM system? (a) for the initial creation, and (b) for on-going synchronization of new customers and changes to existing customers?
2. Credit Management: what is the best practice for update of exposures from SD and FI-AR from each of the different systems? Should this be real-time for each transaction from SD and AR  (synchronous) or periodic, say once a day? (assuming we can control this in the BADI)
3. Is there any particular point to note in dispute management?
4. Any other general note regarding this scenario?

Thanks in advance. Comments appreciated.