Yes, Oracle BI server can be used as a data source to create a data set in the BI Publisher. A newcomer to the Oracle BI might think that since the Oracle BI server RPD is accessible via Presentation services and an ODBC connection, then BI Publisher should be able to access the RPD subject areas, just as Oracle BI can. This logic is only partially correct. BI Publisher does not currently have the ability to cherry pick Oracle BI subject area elements as if using the Analysis Ad-Hoc Editor. BI Publisher has two options to reference the Oracle BI server data. The first is to select an analysis request developed in the Analysis Ad-Hoc Editor and save to the Presentation Catalog. Typically, this will be an analysis request created specifically for the purpose of being consumed in a BI Publisher report. That report is usually saved in a folder location close to the BI Publisher report that ultimately leverages the said data. The second option is to create an analysis request, select the Advanced tab in the Ad-Hoc Editor, and copy the SQL that is generated for that request. That SQL can then be pasted into a BI Publisher data set. The latter option is the best option.
BI Publisher offers third-party or custom integration functionality via a Java API and a set of web services that communicate with the BI Publisher server. These API methods can interface with just about all areas of BI Publisher including user management, translation deployment, managing portions of the catalog, scheduling artifacts for delivery, and more. In many ways, this API is similar to the Oracle BI API; however, for day-to-day functionality to advanced functionality of communication with an application, the BI Publisher API seems to be better-rounded. Keep in mind that the BI Publisher API does not communicate with the BI server directly or vice-versa.
The Oracle BI development hasn't yet flushed out all of the integration points between BI Publisher and the Oracle BI server as of this release. One of those disconnects has to do with the way the Oracle BI Server's scheduler system delivers, distributes, or bursts its artifacts to the masses. Currently the BI Publisher Scheduler, referred to as the Quartz Scheduler, and the Oracle BI Server Scheduler, Delivers, are separate tools. Oracle BI Delivers cannot burst BI Publisher reports, although it may reside in the same Presentation Catalog. However, currently the BI Publisher Quartz Scheduler is much more powerful than the Oracle BI Delivers Scheduler and it has a better API. It has delivery destinations that can be conjured and a more robust failover system that can take advantage of another open standard application--Apache ActiveMQ.
Determining failover and highly available architectures for Oracle BI Publisher in standalone mode poses no major challenges when compared to the HA topology and configuration for the Oracle BI Enterprise Edition. Luckily, when Oracle BI Publisher 12c is embedded in the Oracle BI Enterprise Edition, the BI Publisher HA architecture follows the core HA topology for the larger Oracle BI Server platform implementation. This makes sense seeing how both applications will be deployed to the same managed application server and, by default, share the same metadata database repository schema created by the RCU.