The MV31-W card that you linked to is a M.2 form factor data modem and GNSS receiver. It doesn't have a native front-end for voice calls -- hence why you found it listed as a "data only" card. (note, if I ever say "card" I am referring to the physical MV31 hardware; I will use "SIM" if referring to the telephone company's Subscriber Identity Module smartcard)
As Hastur pointed out in the comments, if you are using a data-only SIM then you will not be able to get voice calls. And that's the end of the story. So your first step is to make sure that your SIM is enabled for both voice and data.
The good news is that all cell phones operating above "3G" are data-only devices; even the "voice only" calls are actually routed through digital data systems. The bad news is that most carriers push this data on a separate processing band that is handled by a distinct RFE from the "cellular data modem" component of the calls. Your MV31 card does not have the RFE made for voice calls.
Back to more of the good news: You can emulate the RFE entirely in software. With the right software you can add a virtual telephone interface to the connection made by the MV31 card (again, assuming your SIM and line of service are both voice-enabled). The software will vary depending upon the cellular telecom provider. About 6 years ago I had a Lenovo laptop that came with a piece of AT&T software that did just this; it was pre-loaded (the laptop came with the AT&T card and SIM), and now days I wish I still had a copy of it. The reason this software is telecom specific is because it has to interface with your specific telecom's voice calling system. And this takes us back to yet more bad news, if your telecom doesn't have (or doesn't allow) interfacing software then you won't be able to do this.
Some follow on points, since it sounds like you may have been overwhelmed by some less than fully helpful sales types.
- Using Asterisk means you will be running a SIP server -- you'll have to have a SIP service provider that has a phone number and you log into them to get/make phone calls. This is very effective for multi-phone systems, but for a single line it is a bit overkill (and a lot of hassle). You'd be better of using something more like Skype at this point.
- VoLTE (Voice over LTE) is the technology I was referring to when I said that phones operating above 3G are actually data only. And it uses specialized encoding software in the RFE and LTE data gateway to connect your phone calls over a data-only network. This is the same end effect as the computer software I mentioned. But the MV31 card is not a native VoLTE encoder, so it can't do this without additional software.
- CSFB (Circuit Switched Fall Back) is completely off the table. The MV31 is a data-only card, it cannot connect directly to the older circuit-switching voice telephony networks.
- You will not be able to receive or place calls on the MV31 from your Nokia's mobile number. At least not without removing the SIM from the Nokia and putting it into the computer, and then switching back when you want to use the Nokia. The phone number is tied to the "subscriber point of presence" -- which is uniquely identified by the SIM. Your computer SIM will have one phone number and the Nokia SIM will have a different phone number. So even if you get voice calling from the laptop working like you're describing, it will be with the laptop's phone number.
A lot of this sounds like you may have been talking to the wrong folks before buying parts (specifically talking to the hardware tech support instead of talking to your cellular telephone company). It is an easy mistake to make if you haven't done this before. Remember for the next time around that you're coordinating both hardware and service, so both need to be consulted about feasibility, capability, and compatibility.
Finally, I'll offer a possible solution for you. Look for a service similar to Google Voice. Either get a new VoIP telephone number, or port your existing telephone number to the online VoIP relay service. Then have Google Voice (or your preferred alternative) setup to forward the call to whatever number you're using on the Nokia. You can then go to the Google Voice site (or use the Voice/Hangouts/Duo software) to make & receive phone calls from your laptop with the same phone number. I mention Google Voice specifically because it is free, and you stressed that particular requirement; but you can use RingCentral, Grasshopper, OnSip, or any other such service if you can't (or simply don't want to) use Google Voice -- just know they have varying price points. The down side is that since you have a non-smart phone, it is difficult to make outbound calls from the phone using the unified Google Voice phone number (both can receive calls on that number, and if you use a smartphone with the Google Voice app [especially Androids, that can seamlessly handle this exact setup] then this whole thing works perfectly)
In the end, using the cellular data modem for only data and then using an over-the-internet telephone service provider (ie: Google Voice) to take care of call handling for both your computer & Nokia sounds like it is the closest to optimal final solution. You'll have one phone number that is used to receive calls. You can make calls from the laptop using that same phone number; and if you upgrade to a smartphone you can make calls from the cell using that number as well. You can send/receive text messages using that phone number. And (as long as you use Google Voice) it doesn't have an added cost beyond what you're already doing -- just the two SIMs & cellular lines of service with your telecom (laptop and Nokia).