Can TransferWise’s P2P matching model work only in two-way corridors, or can it also work in one-way remittance corridors from developed to developing countries?

The TransferWise model, is best known as net-off model in remittances, meaning, there is no money moved between the two countries, only the local demand/supply pair is settled with the supply/demand pair from abroad.

The question is where can it work? It can work almost anywhere, provided

1. The Regulator allows net-off settlements in remittances. In most countries, net-off settlements are not allowed. The Regulator (usually the Central Bank) would most likely like to see the money coming into their country, i.e. inward foreign exchange, and this foreign exchange is surrendered for the local currency. This not only increases the Forex Reserves of a country, but also improves the financial health of the country on the whole. If the regulator has banned or disallowed net-off settlements, then needless to say TransferWise Model will not work.
2. Second element is liquidity. If there is not enough liquidity in both directions, the model does not work. Lets take an example of India. If someone from London wants to send GBP 5,000 to India, the way the model will work is to find someone or a couple of people who collectively would be sending GBP 5,000 from India to UK. If you cannot find the latter, then the model cannot function.

I would say in the end, it is in order of priority, the regulations in the sending & receiving countries and then it comes down to liquidity in the market place to ensure such transactions can be executed.