How big a risk is to abort take-off before V1 with uncontained engine fire and side-wind?
If it happens at a slower speed as you ask, then maneuvering the plane on the runway as it stops would help, even if it's only a 45-degree turn. You might wonder why not do a complete 180 if the runway width allows; that turn is slow and takes valuable time, while a fully loaded plane can theoretically be evacuated in under 90 seconds with only half the exits. It's a smaller risk considering the low-energy abort. A high-energy abort adds the risk of the brakes starting another fire.
As to Flight 1504, there's no need for opinions, as the final report did not fault the commander's decision:

The management of the failure by the flight crew was carried out professionally and in compliance with the established procedures. The same applies to the air traffic controllers, who assisted the aircraft with professionalism and providing maximum cooperation. The commander decided not to interrupt the take-off run despite the right engine fire warning having intervened a few knots before V1, thus exercising the expected discretion and taking into consideration all the available elements that favored this decision. [translated from Italian; emphasis added]

Speaking of Go shortly before V1, it is advisable for tire failures due to the compromised braking:


Source: Pilot Guide to Takeoff Safety - FAA (PDF)