Information exchange will in part depend on the network of the company. If there is no external access to the AX and SharePoint deployments, you will be limited to writing integrations that live in the local network and "reach out" to CRM Online.
That said, you can exchange just about any data you want, using a tool like Scribe. The most basic version of this is to synchronize Accounts and Invoices between AX and CRM, but ou can extend this to virtually any data you want, as long as you create
the attributes in CRM to hold your AX data.
On the SharePoint side, if your SharePoint is public-facing, you can make it hold the documents that CRM would normally attach to a local record. This gives you all the advantages of SharePoint's document management inside of CRM. In the other direction,
you can install the CRM List View component inside of SharePoint to surface lists of CRM data inside of SharePoint. This is particularly useful if you need reporting/dashboards out of CRM for business managers that don't need a license to CRM itself.
The postings on this site are solely my own and do not represent or constitute Hitachi Solutions' positions, views, strategies or opinions.