Is npub.cash anything like pos.cash or selene.cash
nostr:npub1vkgj57k30l2u7wave6t4nua75wjylx3nju6qu4vu7pneghwx8zlsf7q4uq yeah, my new npub.cash address showed up in my cashu wallet settings. Well NWC to Damus via Cashu wallet let me zap one time. Now no dice again - but I’m excited to see how it worked. 
Discussion
I have not tried the other two, npub.cash is essentially a vanity address via one time payment that routes to where ever you want.