Further into ULP territory

I am (still) working with an ultra low power setup. It raises a lot of questions.
I made a few sketches with considerations. I have to order most stuff from China, it takes ages so I can’t just try out all of the ideas.

Does it make sense to have regulator between battery and MCU? (V2_schem.png)
Idea is to let the MCU run on 1.8V 4MHz instead of 3.3V 8MHz, as far as I understand using a regulator should hopefully stretch batterylife by utilizing a larger portion of the battery. I am not sure it adds anything when the device uses <10uA while sleeping.

I suppose using deep sleep on NRF24 combined with a MOSFET controlled booster is okay.
The device will be asleep far most of the time (awake ~1s per day) and I am not too concerned about the power usage of the 2nd booster.

Will a (super) capacitor use less power than a separate booster for the NRF24? (V4_schem.png)

My battery plan is to use a 3.3V Li-ion at about 2Ah.

Hope some of the questions makes sense.