From your app description I think this will definitely get rejected by Apple. Subscription availability, periodical (not more than quarterly) content are required as par Apple's guidelines to be a Newsstand app.
Subscription availability is required because background downloading via push notification makes sense only when user can purchase subscription for your periodical content. This will only make sure that user can opt-in that your app can download content in background via push notification.
This is from Apple's ios Program License Agreement. You can read it from your developer account and BTW you must have accepted this :)
3.5 You may offer in-app subscriptions for free in select territories using the In-App Purchase API subject to the terms of this Schedule 1, provided that the Licensed Application is Newsstand-enabled pursuant to section 3.7 below and You clearly and conspicuously disclose to users the following information regarding Your in-app subscription: • Title of publication or service • Subscription may be discontinued at any time by removing app from device • Links to Your Privacy Policy and Terms of Use
3.8 Licensed Applications offering subscription services under this Schedule 1 must be included in Apple’s Newsstand program provided that, in addition to the requirements set forth in paragraphs 3.5, 3.6 and 3.7, You: • Enable the Licensed Application as a Newsstand app in the iTunes Connect tool • Authorize Apple to select “Newsstand” as the Licensed Application’s secondary category • Utilize the In-App Purchase API, include any additional code, and comply with any other requirements as identified and updated from time to time in Newsstand-related documentation found in the iOS developer library and the iTunes Connect Developer Guide • Provide updated cover art with each new issue • Confirm that the content of the Licensed Application is a periodical (e.g., newspaper or magazine)