Hi Fahad,
At a high level and without further details, your scenario looks feasible. However, I think you will need to carefully consider the effort involved in developing your own WebI data source SDK component vs purchasing a 3rd party add-on. In addition to the APOS option you've mentioned, although I have never used it myself, you may also wish to evaluate the Open BI Framework by BI Excellence.
Regards,
Mustafa.