Sorry this response came out kind of long, but I'm not sure what your background is in this area, so I'm explaining as much as I can. If nothing else, maybe the builder could learn from this, too. 
Do you prefer Z-Wave for a reason? I'm asking because some devices can connect directly to certain Amazon Echo devices via Zigbee, which is a similar protocol often used for home automation — but is different. Some Echo products have a Zigbee "hub" built-in, but none have anything like that for Z-Wave. So, as it seems you've figured out, you'll need a Z-Wave controller/hub that you can then connect to Alexa, over your regular home network and (usually) the Internet. This is not that unusual; lots of people use a hub like Hubitat (or SmartThings, Wink, Vera, etc.) to do this with a variety of devices of different protocols — and in the case of I'd guess most Hubitat users, even Zigbee devices that could be connected directly to Alexa but are done this way instead to leverage the additional power Hubitat provides.
So, if you're looking for a way to connect the lock to Alexa, Hubitat can do this, but it can be tricky. Your inability to get it to added to Hubitat is likely one of two things: either the lock needs to be reset or have a general exclusion run on it first (try the "Start Z-Wave Exclusion" option instead of inclusion before you try again, and follow the instructions for putting the device in exclusion mode from the manual), and you may need to keep the hub close to the lock when pairing it -- within a few feet, especially if you have an older model.
To top it all off, many Z-Wave Schlage locks are a bit picky. The above advice is applicable to lots of locks, but some users seem to have more problems with Schlage in particular (not always reporting status back to the hub, etc.). Staff removed it from the "official" compatibility list a while back for this reason — but they do still work well for many people, and it's possible their newer locks are better. Another thing helpful for any Z-Wave network: having at least one Z-Wave "repeater" on your network is a good idea, more for larger networks or if there is more distance between the hub and device. A repeater that supports "beaming" (nearly any modern device will, but you can check the conformance document from the Z-Wave Alliance to check for sure) is particularly helpful for locks. Most mains-powered devices, like Z-Wave smart plugs or switches, are repeaters, though there are also dedicated repeater-only devices.
All this to say: if you just want an easy way to connect to Alexa and that's it, you might be happier with a Schlage model that can do so directly, like the Zigbee equivalent of this model, assuming you have an Echo device with Zigbee (or perhaps something else from Schlage that does if you don't -- maybe their WiFi ones can too? -- or another vendor). If you're not looking to actually get into home automation or expanding your "smart home" beyond this single device, a full Hubitat system may not be the best choice for solely this application. I'm here because I do think it's great, of course. But most people don't use it just a way to get a single device into Alexa, and the Z-Wave protocol may be best used with some knowledge/care when setting up the network (probably why Amazon picked Zigbee instead, ha).
That being said, if you think it's a good fit, I'm sure people here will be happy to help troubleshoot -- beyond the general tips I gave above! Good luck with whatever option you choose.
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if it paired.
