As far as Terminology, you can just say “home automation.“ IOT stands for “Internet of things“ and refers to a specific kind of technology that covers both residential and commercial uses. It was trendy a couple of years ago, but just not used as much now except by people on Twitter trying to keep the character count down. 
Samsung is really really bad at naming things. It tends to use the same name for two or even three different things. And it will often use terms in a somewhat different way than the rest of the industry, which is confusing.
“Edge computing” was an industry term that’s been around for almost 10 years and referred to a design that moved as much computing as possible out of the cloud and running locally, while still having connections to a central cloud database. So, if you just Google “edge“ that’s most of what you’ll find.
About a year or so ago, smartthings decided that they would call their new architecture (which ran more stuff on the hub, rather than in the smartthings cloud 0) “edge drivers“. That’s OK, it’s similar to the basic existing concept of edge computing, but it is different. And nobody uses edge drivers of that type except smartthings, they are unique to that architecture.
It’s not that any of that really matters, it’s just that it can get confusing if you’re trying to do Internet research.
So, just say “Home Automation,” that’s the simplest and most widely understood term for what we’re all trying to do with smartthings, whether we have hubs or not. And use the term “edge drivers“ when you are specifically talking about the smartthings required code for devices that communicate directly with your hub.
As far as having multiple hubs/bridges, some people hate that idea. Me, I don’t care as long as it doesn’t add to my workload. I don’t expect my plumbing junctions to run through my electrical boxes, so I don’t care if there are two boxes on the wall. Same with hubs for home automation. I think I have about seven now, maybe more than that, but 90% of them I never touch except when I first install the devices. They sit there and handle that traffic, and I don’t have to worry about them. I just see them as part of the infrastructure. But that’s just me. I do know people who hate the whole idea of multiple boxes plugged into the wall, so if that’s a priority for you, that will affect your candidate selection choice is good. 
