Keet isn’t fully featured yet, still in beta. But yes there is no reason one couldn’t create separate keys for separate identities on your machine. Cross device ID is coming to Keet really soon, so we will see if they add in the ability to create multiple or not, but that’s purely a choice on their part for Keet specifically (I suspect they will, and I’ll chat with them and encourage it too, it’s an important UX imo)
But when talking about Pear and the P2P protocol, there nothing at all preventing it.