I'd say your plan is a pretty good one.
The Octane is a good choice. Yes, you can use it on a .22 and it should do a reasonable job there. The reason most people recommend a dedicated .22 can is that they are not very expensive, do a good job, save you from having to clean your pistol can all the time, and (especially if you're shooting a .22 pistol) something like the octane is almost comically big and heavy relative to the gun.
It is often recommended that you go with a 45 can as your first pistol suppressor. It gives you the capability to shoot .40 and .45 and does pretty much just as well on 9mm and below when compared to a 9mm can. This comes at the cost of about an inch extra length and a bit more weight. If you're pretty sure you won't shoot anything above 9mm though, the Octane 9 is probably the way to go.
The rifle can you've picked is a good one. I think here you really need to think about how you like to hunt and how often you do it. If you do a lot of walking and hunt a lot I'd really focus on getting a lightweight can (even at the cost of capability and durability). Something like a SilencerCo harvester might be a better hunting can. The one you've picked is a pretty good compromise between something for hunting and something for ARs. The Saker or Specwar would be good choices but push the compromise a bit more towards range use and away from hunting. AAC has some good options as well though some do complain about their QD system.