Mine is a 2015 as well, but from what I've read they switched over around that time to the 130mm.

Are they quick release or thru-axle hubs?

QR

This Specialized SCS thing is something haha! So like you said, once you switch the derailleur hanger to this, based on this post, you can use any old road disc brake wheelset. For reference, the stock Axis 2.0 wheelset seems to be in the 2000 gram weight range.

For the benefit of future readers, we're looking for a wheelset that is:
700C
clincher
135mm quick-release, 6-bolt disc hubs
10 or 11 speed (11 speed hub will work with a cassette spacer)

The best all around choice is probably the Zipp 30 Course Disc wheelset. $900, 1650gm. It's a wide rim, 26mm deep, tubeless ready, comes as quick release hubs but also includes the end caps to switch to thru-axle down the road. CXray spokes, Zipp reputation.
http://www.ebay.com/...d:g:GPoAAOSwR29ZC4g0


http://www.zipp.com/...isc-brake-clincher/#

For less money I'd look at Neugent Wheels. Good reputation and customer service. (Note he currently has 10% off with code SUMMER).

Neugent C38 carbon clinchers. For if you really wanted carbon. 38mm deep, 1550gm, around $1000.
http://www.neugentcycling.com/product20.html

Neugent A310DCW. Around $500, 1560 gm. 31mm deep alloy rim. A little lighter and much cheaper than the Zipps, but can't be swapped to thru-axle down the road (as far as I can see).
http://www.neugentcycling.com/product33.html


This is a super-detailed post that mentions some other road disc wheels you could consider.
https://intheknowcycling.com/...sc-brake-road-bikes/

HED Ardennes GP Plus disc wheelset is also bang for the buck
You can find them on sale for about $550
21mm internal width
Alu
1650g-ish
Reliable