Hi Leonardo, thanks for testing ZapPlanner!
1. You can make multiple subscriptions, one for each recipient. Would you like to make multiple in one go? what is the purpose for this?
2. I think that can be added, I have added an issue on the repository (https://github.com/getAlby/ZapPlanner/issues). But note that ZapPlanner can't do nostr zaps because it cannot sign the zap request events without your nostr private key. So it's limited to standard lightning payments.