As usual, the Apple (NASDAQ:AAPL) rumor mill has been hyperactive leading up to the company's annual fall product event today. Speculation is rampant about a so-called "iPhone X" with 3D facial recognition, a new Apple Watch with cellular connectivity, and an updated Apple TV that focuses on live TV integration.

Assuming the rumors surrounding Apple's Tuesday event are accurate, it's easy to think that maybe there's nothing left to discover. But despite all the speculation, investors should keep in mind that nothing is certain yet. Indeed, some big questions remain.

Apple CEO Tim Cook onstage at a product event

Apple CEO Tim Cook. Image source: Apple.

How much will new iPhones cost?

There's been some speculation that Apple's iPhone X will have a massive starting price of $1,000 -- or a whopping $350 more than what iPhones usually start at. Will Apple really attempt to pull this off?

At first, a $1,000 starting price for the iPhone X might seem a bit out of hand. But assuming the iPhone X has higher storage tiers than traditional iPhones, and assuming it has a larger display, the pricing could arguably be in line with how Apple prices its iPhone today. The iPhone 7 Plus, for example, costs $969 when purchased with 256 GB of ram.

Supporting this line of thinking, Apple is expected to debut an iPhone 8 and 8 Plus, which will reportedly have the same form factor as the iPhone 7 and 7 Plus, alongside the iPhone X. Apple could easily market the iPhone X as a premium option beyond these two devices, starting its storage tiers much higher.

A higher price tag would test Apple's pricing power. But history shows Apple would probably pass the test with flying colors. After all, Apple has slowly added higher-priced iPhone options in recent years, starting with the iPhone 6 Plus' introduction in late 2014 -- and investors have willingly paid up for the new devices, driving up the iPhone's average selling price.

When will iPhone X shipments start?

On Monday, KGI Securities analyst Ming-Chi Kuo said that Apple's new flagship iPhone X may be facing some production shortages. Kuo's report of low initial production for the iPhone X isn't the first. These rumors have led to questions about when Apple's new iPhone will actually begin shipping to customers.

Apple normally begins taking orders for its new iPhones on the Friday following the launch, beginning shipments on the second Friday after the launch.

But will Apple only have its rumored iPhone 8 and iPhone 8 Plus ready for shipments in September, opting to begin iPhone X shipments later in the year?

Can Apple surprise us?

Given how accurate rumors ahead of Apple's iPhone 7 and 7 Plus event last year turned out to be, it's a wonder if Apple can keep secret any new major surprises before its product events. Bloomberg's Mark Gurman, who is known to be the golden standard when it comes to Apple rumors, may have even already spilled the beans on the new smartphone's "crown jewel," 3D facial scanning.

But rest assured, it's still possible that Apple will have a surprise announcement. Though given the breadth and scope of Apple's sprawling global supply chain, any surprises will mostly likely be either related to software, services, or one of Apple's smaller product categories, like Apple Watch. Indeed, Apple's 2014 announcement of its Swift programming language totally caught everyone off guard. Further, the Apple Watch's entire design was mostly a secret until Apple unveiled the device in late 2014. 

Of course, investors shouldn't get their hopes up for a big surprise. Chances are, the rumor mill has already created enough excitement for Apple's upcoming products.

Apple's product event will start at 10:00 AM PDT on Tuesday, September 12. The event will be live-streamed on Apple's website and on Apple TV.

Tune into Apple's event to see if Apple answers these questions -- and stay tuned at The Motley Fool for some post-event analysis.