DoJ
ISabeli and Juliette-chan,
if you are successful in the preliminary rounds and manage to get to the FI, you will be given a form where (among zillion other things) you need to write when you would be able to join and whether you have any other planned events.
I had my FI yesterday and I wrote that I have some formalities at the uni connected to my thesis in November and would therefore be able to join in December.
I guess that as long as the delay is reasonable and justifiable, it should be OK.