Assuming the FAO flight which routed via NTE departed on time yesterday the OAT would have been 23C and the wind 250/10. I seem to remember that Second Segment Climb considerations tend to be the limiting factor for R/W 24 departures, so it was perhaps that rather than actual runway length which made a fuel stop necessary.
I think easyJet originally blocked off half a dozen seats on SEN-FAO when it commenced in 2012 but I don't know if that is still the case. There was at least one instance last year where a large number of male golfers caused payload/range problems so perhaps it was something similar this time around. Perhaps someone here knows the actual details.
I think the A320 was unrestricted to FAO when it operated numerous times during April when some 180+ pax were carried on some departures I believe.