[Verizon Samsung Galaxy S7 ROMs, Kernels, Recoverie] cognitivedissonance:
Alright, somehow I got this worked out. Here's what happened:

1st try:

Step 4) Ran as instructed in OP and made sure to run root.bat as administrator (shift click method.) The command window popped up, some commands ran REALLY fast (I couldn't read them) and then the command prompt closed immediately. The phone didn't do anything and just stayed on but I just assumed that everything had run the right way, so I proceeded to step 5 and installed Flashfire. It installed but when it opened it just stuck on the message that essentially indicated that I didn't have root and it was trying to find it.

2nd try:

Step 4) this time I just double clicked root.bat instead of running as administrator. The command prompt stayed up and the commands ran much more slowly. I wasn't sure if it was hanging or actually doing something at first. Took a minute or two to do everything and then automatically rebooted the phone. When the phone turned back on I opened Flashfire again and it complained about needing to update SuperSU to a version beyond 2.4. I looked at the SuperSU and it was version 2.72 or something. Went back to Flashfire and suddenly it stopped complaining. It just continually clocked on the Acquiring Superuser Permissions message (or something like that) but never prompted me for them. I waited about 5 minutes and still it was clocking. I tried rebooting a couple times and I think maybe at one point it requested root permissions, but I can't recall if that was before or after I went on to "3rd try." Regardless, even after I allowed it permissions and it showed in the SuperSU app as being granted permissions, it still just clocked.

3rd try:

I figured something was wrong with SuperSU or Flashfire or both. I searched and found jrkruse's original thread (https://xdaforums.com/verizon-s7-edge/development/rom-t3569416) and read his instructions. I noticed that in what seemed to be analogous to Step 4 here, the zip file he was using was different. Namely, his uses S7Root_Unroot_SU_2_79_Simply_Root_Flashfire.zip, so I downloaded, unzipped that one, and then I followed his instructions to open a command prompt by shift clicking and run root.bat from within the command prompt. The commands went off similar to the way I noted in "2nd try" but I noticed this one seemed like it installed Flashfire. The phone rebooted like before, and I went back and tried Flashfire again. Same thing happened - lots of clocking. As I was reading more and trying to figure things out, all of a sudden I think it decided to continue and eventually got into the Flashfire app properly. No clue if I just waited long enough or what was going on, but it took a really damn long time for Flashfire to get root / su permissions and recognize that it had them....

Anyway, from there onward it was smooth sailing. One oddity I noticed was that until I selected "wipe all data" in Aroma, all the data on the phone seemed to remain intact for the most part. I'm wondering if perhaps wiping the phone prior to beginning the process wouldn't have been a better idea (especially because I noticed that the phone tried to start a data restore at some point over wifi, which was still connected.)

Anyway, in the end it seems like he's up and running properly so that's good. I appreciate the guide.

Suggestions:

1) Probably a good idea to either ODIN flash a full-wipe file or at the very least do a factory reset before starting

2) An explanation about how long certain steps will take would help set expectations and reduce confusion. Example: in step 4, it should take about a minute to run the commands in the prompt and then the phone will reboot. If command prompt just flashes some commands super quick and then immediately closes, it failed and you should try running it a different way (either as administrator, not as administrator, or from within a command prompt.) A disclosure about Flashfire needing to be granted root access and then taking a really damn long time to recognize root permissions and get into the actual menus of the app would be nice too.

3) Might be a good idea to just use the zip that includes flashfire in step 4 - the phone is already very laggy, courtesy of the engineering kernel, so installing things via touchscreen is time consuming and seemingly needlessly annoying when there's a zip that does it for you

4) A detailed walkthrough of the various options in Aroma installer and what they do / mean would be helpful. I ended up guessing on at least 3 of the choices and hoping for the best. If there's something like this out there somewhere already, a link to it or a quote would obviously be sufficient.

Anyway, thanks again!!