As far as I understand IBC is a protocol suitable for Cosmos / Tendermint based blockchains (guaranteed finality). Other blockchains, like Bitcoin and Ethereum don't have guaranteed finality.

For those without guaranteed finality, inter-communication is created using a "peg zone". A peg zone is basically an account-based exchange, in which you maintain a blockchain node which will act as a buffer between those two. It's an "application blockchain" that takes care of moving back and forth tokens from one blockchain to another and maintain consistency.

Now, a peg zone between Hive and Cosmos will be just a DEX, a way to allow price discovery by creating liquidity pools and function as a decentralized exchange. That's how Hive Engine works (to the best of my understanding) right now with all the tokens minted on its layer 2.

A peg zone between Hive Engine and Cosmos will be a bit more advanced, as it will also allow for "wrapped" Cosmos in the Hive Engine layer 2, and for "wrapped" Hive in the Cosmos ecosystem. Tokens sent from one blockchain to another will cease to exist on the origin blockchain, but continue to live in their "wrapped" form on the target blockchain, until they are redeemed back on the origin blockchain (or forever in the target blockchain if they are not redeemed). The reason is "wrapped" tokens must be maintained by smart contracts (that's how Cosmos - Ethereum bridge functions, there are smart contracts on both sides that are minting wrapped tokens on their corresponding blockchains once all the required signatures are fulfilled). In Hive we don't have (yet) smart contracts, which will allow minting ERC-20 compatible tokens (or any other standard that those smart contracts can implement).