Have IQ Panel 2 & Alarm.com, looking at adding SmartThings

So the subject line basically lays out my situation. I’m looking for more home automation/customization than the alarm.com automation allows. In particular, I’m looking to install a GE Z wave Plus in-wall motion sensor smart switch, but have the profiles/activity differ depending on time of day. I stumbled across a thread on this forum that had a custom DTH/routine (not sure of the lingo yet) which would accomplish exactly what I need.

I’ve been considering a SmartThings hub for awhile, but wanted to know if and how I integrate it with my current Z-wave device setup, which all runs through the IQ Panel 2. Every motion sensor, door sensor, garage door, and light are connected to my IQ Panel and I automate them through Schedules, Rules, and Scenes on alarm.com. But customization is limited.

My questions are:

  1. Is there still a big benefit to adding a SmartThings hub?
  2. If I think about it in terms of a primary/secondary relationship, which device would each be (ST Hub and IQ Panel)? I’m guessing one of them just becomes a “repeater” of sorts?
  3. Can I keep all of my existing sensors but still setup ST rules to run based on activity from those sensors to operate lights, locks, garage doors, etc?
  4. Would I be better off with a v2 or v3 hub (assuming price is equal)? I know v3 has lower specs, but it sounded to me like some reviewers preferred the newer app with v3. I don’t need the wifi in v3, nor do I need battery backup in v2 (not sure what ST would operate if there’s no electricity).