Hello and welcome,
There is no support for POS rewards currently or in the future.
If you wish to offer rewards/interest/etc you can do so using the Airdrop extension. You can set up a recurring airdrop that approximately matches the rate of return of your PoS rewards. The PoS rewards are to your PoS wallet, while the Airdrop debits the user balances. This is necessary since one wallet holds all the balances, and there is no 1-1 correspondence between blockchain addresses and user balances. Let me know if you have any questions on this.
The current codebase is obsolete. In a few months I will be releasing the new codebase (wallets6) which is essentially a complete rewrite of the plugin and all its extensions. So, not much point in pushing features on git right now. See here for details: https://www.dashed-slug.net/upcoming-bitcoin-and-altcoin-wallets-6/
with regards
P.S. I have moved your other question here as it was not related to all this.