I hope you are doing great.
1. Please look at the power down example that we provide in the SDK.
/* Keep All SRAM banks for warm boot */
config.pm_config |= PM_CFG_SRAM_ALL_RETENTION;
2. I am not sure if I am following your question. Do you want to send in the payload the short address and the mac address?
I think the next API could help you to request the mac address of the node zps_eAplZdpIeeeAddrRequest
If you already have the short address.