I’m not a coach but as long as you can eat after sundown and don’t have a physical job my experience with 5:2 fasting suggests you should be able to deal with max hour long sessions a few days a week. It won’t be perfect and you might end up wearing yorself down though so take things easy!
A couple of base sessions e.g. Z1-Z2 touching Z3 eventually would be ok. I wouldn’t recommend intense intervals since you might be low on glycogen and this might add extra load on your system, but fasting and using fat as fuel would be of great help to your overall fitness. Plenty of hydration when you still can will be extremely helpful to get you through.