The "Skywalker" of the title may in fact refer to Rey, but as an honourific rather than a reference to her actual bloodline. Perhaps it's a code name that she's taken up within the Resistance in order to honour Luke's memory. This could potentially lead to a powerful "I am Spartacus" moment, where the First Order tries to ferret out who the rebel Skywalker is, only to be met with multiple Resistance fighters claiming to be Skywalker in order to protect Rey. In doing so, they would all, in a way, become Skywalker, subverting the Chosen One narrative by allowing an entire group to claim the hero's mantle.