The wireless charger will come with a Micro USB cable that you will connect to the AC adapter (in this example, the PowerPort Speed 2). So you wouldn't need to purchase a separate cable specifically for the wireless charger.
For the 7.5W wireless charger, you will need a Quick Charge 3.0 AC adapter (which is why I mention the PowerPort Speed 2). Why, you may be wondering? Basically, any wireless charger above 5 watts requires more than 5 volts as there is some power loss in the conversion. Quick Charge 3.0 chargers can deliver the extra power that is needed. This is why you'll see this little footnote on the page for the 7.5W wireless charger:
"Do not use Apple's 5V / 1A stock charger or a computer's USB port to power your Anker wireless charger. iOS 11.2 required to access 7.5W fast charging for iPhone. Quick Charge 3.0 wall adapter required for Fast Charge Mode."
If you go with the 5W wireless charger, then the PowerPort Elite will give you enough juice and save you a little money.
I hope all this makes sense! Let us know if you have any more questions.