Only the lens holder is "open source". They don't provide design files for the lenses themselves.

Interactions with the company have been very disappointing. They don't pay attention to their own Twitter account or the common VR subreddits (/r/virtualreality or /r/oculus, though they post their own press releases to them, so they certainly know they exist) and they had the spam filter on their own support email line configured poorly. There were about two weeks between when the Sky first started going out and when Wearality started answering questions about what exactly they meant by "150 deg FOV". Their official replies were very derisive towards anyone who had done their own measurements and complained about people not signing up on their private forums to ask questions. Sorry, I personally think private vendor forums are a dead concept. I'm certainly not going to sign up to ask one question in a forum that has 0 posts. They've not updated any of their marketing material to even mention 7" displays, let alone that it's necessary to get the full 150 deg FOV. It's not even entirely clear from just their own information that 5" displays won't show as wide of a view as 6" displays, you're left to either figure that out on your own or hope that the separate set of clips change the focal distance (they do not).

In the end, they define 150 deg FOV as the visual angle between the eye and the rear lens aperture. You lose some view around the edge where the lenses only show the internals of the frame. Also, a 6" screen phone is not large enough to fill the view of the lenses, even though the max size of clips they provide is for 6" phones. My own measurements put the Sky with a 6" phone at about 110-120 deg FOV. That's certainly better than Google Cardboard. Wearality claims you have to use a 7" screen to fill the lenses. I suppose the holder will stretch to fit such a tablet, but it's very much not designed for it, and considering they provide separate holders for 5" and 6" phones, I would expect a 7" tablet to need a clip scaled for it.

Let me reiterate: it's the best smartphone-class viewer I've ever used, even if it doesn't live up to the claims. And I believe one could expect to get very close to 150 deg FOV out of a 7" phone. Of course, that extra inch will be so blurred you won't be able to make out any details, but the extra light is nice for the periphery. You'll have to modify the holder clip 3D models and print them yourself. Wearality does not provide a full package that is capable of 150 deg FOV out of the box.

It's also not so cheap. I Kickstarted at $130 to be able to get the very first shipment of the lenses, spacing frame (there are 4 lenses, two per eye, and they have to be spaced correctly), the 5" and 6" mounting clips, a carrying bag, a hat (with a flat brim to be able to clip on the device so it can be used hands-free), t-shirt, and a patch. They now are offering additional purchases to some backers of the lenses and frames with one set of clips and no mention of hat for $99. I have no idea what the retail price will be, but I'm assuming it's going to be more than $100.

As for your other question, there is no integrated input mechanism. That's not a problem, though. The framing of the Wearality is completely open, so you're encouraged to touch the screen with your finger. That open frame design is great for portability. I recently showed it off to a bunch of friends and family at a party. Had it in my pocket right next to my phone, just pulled it out of the provided bag of holding and clipped it on while I waited for the Tuscany demo to load.

Also, Google Cardboard has gotten away from the magnet. Turns out magnets aren't nice to compasses, who knew? In the 2.0 version, it's now a strip of copper tape that connects the finger to the screen through an origami bumper button.

Finally, most people who use their smartphone viewers frequently end up buying a headstrap of some kind and a bluetooth gamepad or keyboard.