Hello. Is it okay to use just one 3.3V supply? I would imagine that 3.3V on the battery input plus the 3.3V "legacy" input connected together should work okay. The voltage would go through the 20 milliohm resistor to get to VIN. Would that be okay or is there a better way? Do I need to populate the charging circuit in order to increase my options?

I'm planning on using a supercap for the 3.3V_uP_BATT so it's connection is separate. Thank you for your help.