I prefer using my own experience… Dr Berry has about as much an idea as I do about what “breaks” a fast.
Dr Fung says some cream in coffee is ok. Im happier with cream in my coffee and I IF everyday and have done extended fasts with cream in coffee.
If the OP can do IF with cream in coffee more easily than without I’d say go for it.
If you want to achieve autophagy maybe not but as no-one really understands the mechanics of autophagy yet then even that is up for debate.