micropayment channels, n-m addresses, interoperability
Not necessarily interoperable. 

Firstly, libraries have to agree on what kind of parameters to exchange and how they are exchanged. There's no guarantee that the parameters required by bitcoinj and libbitcoin are the same. 

Secondly, it is now considered standard practice to create P2SH transactions regardless of what kind of transaction you're setting up, unless it is P2PKH. In the case of P2SH transactions, you then have to assert that the payment channel protocol would also be able to parse/recognise/understand the redeem script provided by service provider of the payment channel (assuming that you're talking about a single-direction payment channel).