Asking for add'l detail on API formats

From the Eniro RFP:
We believe that our specifications and exact examples of the, mainly, event driven messages are sufficient enough for you to estimate the integration / customization cost on your side. We do expect you to fully align with this setup, either via core functionality or via a separate integration service translator on your side, managed and monitored by you.
The reason for us pressing on this issue is that we do have multiple fulfillment systems for different purposes and we want to align the integration patterns regardless of fulfillment system. Batches, feeds, daily bulk loads are not even remotely considered an option. It drives excessive cost due to test-costs and lack of transparency.
The formats (xml vs json vs csv etc) and the methods (RPC API like WS or SOAP, Active MQ, Files on ftp-share etc) are all however subject for change and alteration based on your preferences. Preferred is XML via Active MQ but our current setup is facilitated via XML and RPC SOAP interfaces.
• Please provide a rough order of magnitude for these integrations, if not already possible to handle through your standard integration already defined.