Why would they add lightning to a laptop? That wouldn't seem to add any functionality. Android/other users would have zero use for it, and they need this laptop to be attractive to everyone.
I could be wrong, but don't think Apple's first concern is for the Android users. The MB works as a product because it's part of the Apple ecosystem. It's already crippled by only having one combo data/charging port, making iCloud, AirDrop, and AirPlay essential tools for the average user. Regardless of whether it's a 2nd USB-C port or not, is not going to eliminate the need for adapters and dongles for those who really need a second port.
If Apple adds Lightning to the MB, it serves primarily the Apple ecosystem -- Lightning headphones, adapters and accessories suddenly become useable natively on the MBA. Currently, there is no female Lightning adapter to male USB-C. That's ether by design, and Apple plans to drop Lightning altogether sooner rather than later, or Apple is planning to introduce Lightning to the MacBooks; or they've royally screwed up (which is not outside the realm of possibility). Adding Lightning would allow iOS users to instantly have an assortment of adapters and dongles available for their MB, not to mention instant compatibility with their iPhone & iPad cables and chargers. It would also reduce Apple's manufacturing costs, by allowing them to make one device for both platforms.
And then there's the Lightning headphones. Maybe Apple removes the headphone jack, and includes an adapter. If it's Lightning, then Android users aren't deprived of anything they don't already have, they just have to use the adapter for their headphones, or maybe they use their BT headphones instead. However, if they want to invest in Lightning accessories, they have a fully functional extra data port that they don't have now, which will allow them to transfer data, charge their MB while the USB-C port is in use. And Apple profits in the process. If an Android user already has a BT headphone, then whether it's a Lightning port, or headphone jack, it's just as wasted on them.
If Apple wanted to add an additional port, they probably would have done so already, and let customers buy a USB-C to headphone jack adapter, with the rest of the dongles, docks, adapters and cables required to do anything but charge the MB. By adding Lightning, they are servicing their Apple customers, keeping them in the fold, giving them incentive to buy a MB for which they may already have Lightning accessories, and taking nothing away from non-Apple users. If an Android user buys a rumored Galaxy 8 without a headphone jack, while they may need USB-C to connect their headphones, if they're using a MB, then they are already used to carrying around extra stuff, so it won't change anything. Indeed, Lightning would offer them a second port to use with a Lightning to USB-C adapter, which is one more than they currently have.
Or, Apple will replace it with USB-C and drop Lightning on the iPhone, as they eliminate ports altogether and go with rumored wireless charging. Either way, customers will still need an adapter to connect 3.5mm headphones to the MB, and the iPhone, and an jackless Android, so that doesn't really make it any better for Android users than adding a Lightning port specifically for Apple users (and likely serves far fewer), at least until Android users are mostly using USB-C Android phones, which is likely years away.
