I have a couple of recs, especially since this is your first system.
I would save some $$ and install the 7610. It does not sound like you are planning a super complicated system, and especially if you are using 4 gauge wire. That's really too small to carry winching or starting currents, and since the 7622 is desirable only because of those two capabilities, I'd use the 7610. Unnecessary overkill is an expo trait, but not better.
Even with a 7610, I would recommend 2 ga wire. It can carry fairly large loads (and winches come with 2 ga standard). The 2 ga cables from the positive terminal of each battery need to be fused with a 150 amp fuse right at each battery.
You don't need a ground bus unless you want one.Just connect the negative terminal of each battery together-that's your ground bus. Then ground the ACR with the recommended small fused wire.
You don't need a "safety hub". Just an ordinary fuse panel is perfect and much less expensive. The Blue Sea panels are sort of the gold standard. If you are just running normal loads, like a fridge, radios and some chargers, 8 gauge will be sufficient to supply the panel. Just make sure the 8 ga wire is fused right at the #2 battery.
Regarding batteries-Again, this is your first set up, don't go overboard. A normal RV/Marine deep cycle battery will work great for many years. There are more reasons not to use Odyssey batteries than to use them. If you've been reading here, I don't know why you would give them a second thought. All batteries eventually fail and there is no data to suggest that one is better or longer lived than another, I'd use a less expensive flooded battery. I am running 6 of the RV/Marine batteries in 3 vehicles from Costco with good results.
I am a big fan of the high quality fixtures from Blue Sea. Their fuse blocks, panels and other components are very high quality. But if you set your system up as I suggest, you'll save $300 or more and preserve all the functionality you want.