Where to begin…
I guess, since this is smartthings, we’ll begin at the end, Since discoverability has never been high on the SmartThings list of features.
The use cases you describe are certainly simple, but they are not possible with the new app. That’s because the new app does not at present allow you to set the smart home monitor armed state ( also called the “security mode“) In any way except by time of day or Opening up the app and manually changing it.
This is a huge change from the classic app where you could create a rule to set it based on anything that smartthings could recognize. So in the classic app, you could change the smart home monitor armed state because a particular person unlocked the door, because a particular person got home, because any device you liked was used (including the Iris Gen 2 Keypad and various panic buttons or keyfobs), because you gave a command to Amazon Alexa in your car, etc.
And you could set restrictions around any of those so that they only worked at particular times of day, they only worked when particular people were home, they only worked in specific “location modes“ and more.
Essentially you could set your system up any way you wanted with the classic app.
With the new app, all of that went away, and that appears to have been a conscious decision on the part of the company because it has now been almost a year and there of been multiple updates to the app since that time without adding back any of this particular functionality.
They have also announced that eventually the classic app will be going away, but they haven’t said when. More on that in the community FAQ detailing the differences between the two apps:
SPECIFIC differences between "SmartThings (Samsung Connect)" and "SmartThings Classic"
For now, you can use both apps if you want to, and quite a few people are.
If you have one of the newest hubs, you have to use the new app to set it up.
If you have a Samsung brand smart appliance or smart television, you will need to use the new app.
But you could use the classic app for other things like automations that change the security mode. Except, of course, for the problem that they’ve said the Classic app will be going away eventually.
This is a huge issue for some of us. I myself am quadriparetic. I have to have hands-free control of locks and arming/disarming because my hands don’t work.
Regrettably, neither version of the app works well with voice navigation right now. And that problem has been going on for almost 2 years, so again, I’m not expecting a quick resolution. So if I had to use only the new app, I would no longer be able to independently come and go from my house. For me, that’s a really big deal since the very first use case that ever brought me to home automation 4 years ago was a totally hands-free smart lock.
Anyway, the first decision you will need to make since you are essentially starting from scratch as far as Smartthings is concerned is are you OK with the system that can’t do any of the use cases you listed in your first post. Since that’s what smartthings will be once the classic app goes away Based on where it is today.
(I know there are many people comfortable investing time and money in something based on what the manufacturer has said they intend to deliver in the future, or even based on what they hope the manufacturer will deliver in the future.
In my particular situation, I just can’t do that. I buy things for what they can do today and if a manufacturer says they intend to discontinue something, I take them at their word and evaluate their product based on the absence of that discontinued item.)
So, that’s the first important question before we start diving down the rabbithole of all the other questions. Do you want to consider smartthings as a replacement for your Iris system given that, using just the new app, it can’t do any of the things you listed?