Are you saying AR would be the chain that runs ZK verification? Yes, it would work, with AR being the bottleneck. This is essentially taking the same roll-up approach taken by the Ethereum community, how is AO then different than multiplying ZK roll-ups by 10-thousand times on Ethereum?
Yet still, inter-L2 communication is very crucial. It has to be the L1 that offers verification, IMHO, because L1 is the synchronization point.
If I may be even more blunt, I don’t think optimistic verification is secure in an async setting without introducing a sufficient challenge peroid (which is sound, but goes directly against the scalability claim). By async setting, I mean either the actor programming model offered by ICP or AO, or the inter-L2 communication between ETH roll-ups.
ZK verification in an async setting would still either require a single L1 at the base layer, or relying on the replicated computation (because ZK verification is still computation) of each chains/subnet/shards running consensus protocol.