Are there any headways being made for BTC, ETH, other blockchains cross-talk?
Blockstream for Sidechains: A sidechain is a blockchain that validates data from other blockchains and enables other assets to be transferred between blockchains.
Interledger: The protocol for connecting blockchains.
Blocknet: The Blocknet is a revolutionary advancement in cryptographic technology: a true peer-to-peer protocol between nodes on different blockchains. This is the foundation of a technology stack incorporating an API and an application platform, which enables open-ended application possibilities and vastly reduces development time.
Note: I haven't tested any of these services.