Laptops that have expresscard can use an adapter that supports PCIe which you can than use with the ASUS PCE-68 but powering it depends on how many watts the card uses, 5W or less from usb while any higher via the common adapter. Non windows OSes can team multiple different interfaces together, this means that you can use multiple usb wifi adapters but this requires configuration though i am not sure how well this will work.
Another thing you can do is use wire (maybe 2?) and an access point to connect to the router.
Instead of usb wifi you can try using miniPCIe because there may be AC1900 miniPCIe cards.
Or just wire everything up with gigabit ethernet. Despite the great speeds claimed by AC wireless the practical speeds you get are very very low that wiring up everything is the fastest way to go even though ethernet is just 1 Gb/s commonly.