Yes, you can use your sub0hm mod with any tank that has coils rated at your lowest resistance, some devices won't go all the way to 0, but if you decide to go MTL your best deal for the equipment will be getting a slightly smaller, less powerful mod to go with it, and sometimes folks enjoy the smaller form factor, etc. I think you've gotten some good suggestions to get you going.
Every coil lasts a different amount of time, and it does depend on many factors, including how often you vape, how much liquid you run through your tank, amount of flavoring, sweeteners, and VG/PG ration (including, IMO, the airflow setup and size of tank). For example, I can run Nautilus 2 coils in my Kabuki and they ALWAYS last longer. This setup was DESIGNED with the idea of creating the best flavor out of Nautilus 2 coils, and it seems (to me) to get the best coil life as well. Even though it's only 1 ml larger, though it does have what the site called "revolutionary" airflow. With that said, I'm glad to offset some of the costs of coils with that tank, though I do still use my N2 as well, every day.
Depending on which MTL setup and how you are running it, I'd expect to get anywhere from 5 days to 2 weeks (and that's usually folks without gunking factors) though there are ways to extend that time, for example I wash and reuse my coils once before they go in the dead coil jar, which is for the unlikely event that I can't get coils and have to rebuild them, which I have heard is technically possible. Some setups just have better coil life than others but I can't really judge too much about the various differences as everyone's different. I have one juice I save until a coil is on it's last legs-- storebought coco which I really enjoy, but it is a coil-killer on day one, or day 15.
I think Brother Bob gave you some good places to do research. There are still some great MTL setups out there, and having a backup as a sub0hm, I did that for some time before deciding I kind of hated it, and retired it. My sub0hm tank went elsewhere, it's a quitters tank since my son gave it to me after he quit vaping, then I quit smoking with it, and so I wanted it to continue the fantastic job it was doing to continue helping smoking quitters quit. With that said, subohm can be useful for short breaks where you need to vape swiftly. though I've gotten rather adept at opening my airflow, turning up my watts a bit, and just chain vaping in those situations, so I can make it work... Most tanks have a great deal of versatility, and the N2 comes with a 0.7 coil and a 1.8 coil, so you can do restricted lung hits with that coil if you want (you can also run it at lower watts, airflow, and it's still a MTL tank, at least for me) and I do enjoy the flavor and longer life of the 0.7 coil, since I have gunking factors, I have to run max VG in my tank as I'm sensitive to inhaled PG.
Good luck with your setup, and yes, things become less confusing as you actually do them. This forum got me coilbuilding, and trust me, that's not really something that's within my skillset, but with the right tools and the interactive cliffnotes I got (questions answered on this site) I can almost Build with Confidence... Well, almost.
Anna