Well they're talking of 4 aircraft initially rising to 6 later in the year. Unless there is still going to be a mass exodus they have enough pilots.
There are very few cabin crew left in LGW so they are going to need most if not all the girls from SNN back pretty sharpish I would suggest.
VEX are going to need the BRU crews.
With regard to crewing and OPS staff they have been running enough staff for two aircraft, double that initially, then add another two later in the year and you should have your answers as to how many are likely to be needed back.