NodeMCU power via battery + battery charger + booster
The nodeMCU can be powered by the TP5046 module by connecting it to the '5v' and GND pins.

You don't mention which i2c module needs 5v but most of them can actually be supplied a range of voltages. They often have an onboard voltage regulator which drops the '5v' input to 3.3v.

You probably don't need the boost converter and you should first try it without. It will be more efficient this way.