Power generation strategy
You have various supplies going off 4.5 V. Assuming a LDO to get 3.3 V digital and analog, instead pick a voltage for 4.5 V that is just above the minimum drop-out of those two LDO. For example if they have a drop-out of 300 mV, I would use 3.3 V + 0.3 V = 3.6 V, probably using 3.7 for some margin.

For 3.6 V (Li Ion) to 12 V @ 100 mA there are a variety of switchers with internal FET from TI in the ~150 mm and ~$1 range. The linked page lets you choose based on efficiency, cost and size.

Current from 3.3 V (digital) to digital rails is 700 mA (1.2 V), 500 mA (3.3 V) and 10 mA (2.0 V). That's 1.21 A input into the 3.3 V LDO (from 4.5 V) and 1.45 W lost. I would consider a switcher for 1.2 V. Or an LDO from the input, rather than 3.3 V.

Be careful with your sequencing, especially when using switchers. Some parts require power to come up in a specific order.