My thoughts:
(1) Yes, the hot core airstream is not normally reversed on modern high bypass engines, unlike the older JT8D-type. I would guess the residual thrust to be about 20% of that when the cold stream is also at forward idle.
(2) For sure the brakes get hotter after a RTO - much hotter, reaching peak temps about 15 minutes later. With the aircraft parked there is no significant airflow to dissipate the heat. Google for some certification RTO trials for video evidence - one of the most hazardous parts of the certification process.
(3) See the answer to 2 above. Brake fire very likely if close to MTOW and near V1.
(4) Evacuating pax via slides should always be carefully considered and not done lightly as injuries are virtually inevitable from a large aircraft. You would want to consider all available information from windows, other aircraft, atc, the cabin crew and the fire services time permitting. Ask yourself the question 'Will they be safe staying on board' If the answer if yes, then do not rush into an evacuation, but remain flexible should the circumstances change.