Assuming your power bank is capable of actually keeping the voltage > 5V when each port draws 2.4A, and assuming you’re using high-quality USB charging cables that don’t drop the voltage too much, then yes, that power bank could do it.
An alternative is to use a separate battery, and a separate DC/DC converter for each.
You can power both the Jetsons and the Raspberry Pi through pins 2/4/6 on the 40-pin GPIO header.
Thus, you could hook “big battery” -> 3 separate 5V/3A DC/DC regulators -> 3 separate boards.
Just make sure you get a good undervoltage warning/cut-off device for the bigger battery, if it doesn’t have one built in.
This is a three-cell battery at 5200 mAh, so it’s the same energy content as a 15600 mAh USB power bank: https://amzn.to/31Lo25Y
These are regulators that output adjustable voltage; you should adjust them to 5.15V using a Volt meter: https://amzn.to/2KOc8li
Alternatively, these are 5V regulators that output USB: https://amzn.to/31KgCAc
This is an undervoltage warning device: https://amzn.to/31PckaR
Add some thick DuPont connector wire and some soldering and you’ll do great!