I see you're leaning towards the route I went with my 2wd for dealing with snow. ...and getting into more complicated responses.
Unfortunately, there are no aftermarket supplier that I am aware of that makes a cabin select-able locker for the 7.5"ford axle. It's either carrier replacement Limited slip (clutch or torsen type), or what's called a lunchbox locker, which replaces your current spider gears. These do operate automatically, but you can't necessarily turn them off or operate them from the cab. They work with the throttle, when you press on the gas, it cams two parts outward from the carrier cross-pin and engages specially designed teeth, that lock the wheels together. When you take your foot off the gas, springs push things back apart and your wheels spin independently of each other again. It takes some getting used to and a change in driving habits, but many people have them and like them. A Detroit locker will do much the same thing but is a full replacement carrier, and is much stronger, though you really don't have much to worry about with the 2.3L lol.
Popular lunchbox Lockers include:
Powertrax Lock-Right
(example)
Powertrax No-Slip (different from Lock-Right?)
And as an example, the
Detroit locker
(I couldn't find the "Spartan Locker"?)
The
Detroit Tru-Trac is the Torsen L/S, so don't get the two confused
That's just about it for the 7.5" unfortunately. Occasionally you may need bearings, but only with some, most will have everything you need, anything else would be available at your favorite local parts store.
If you step up to the 8.8 (which would be the axle replacement), a whole 'nother world of options opens. The 2 biggest 8.8 options for a cab-controlled select-able locker are the ARB (air powered, so you need a compressor, which is handy to have in it's own right), or the Eaton E-locker, which only needs a 12v power source.
Though I used an Explorer 8.8 with an ARB in my truck, I used the 10" drums. Explorer 8.8's are the biggest source of disk brake swaps, though not really swapping disks onto an axle, as much as just swapping the axle assembly that has disk brakes already on it. I did a bit of reading since first responding to your post lol.
I replaced everything new in mine, R&P, all bearings, all seals, all brake parts, basically everything new except the shafts, housing, and backing plates. And with the ARB it came to about $1900. With all work done myself. add another $300-600 if you're having it done elsewhere for labor. Axles can get pricey quick.