Can I replace my AIO fans with reverse-blade fans and reuse the originals as exhaust?

The airflow plan should work, although three bottom intakes plus three side radiator intakes with only two exhaust fans could create a strongly positive-pressure setup. That isn’t necessarily bad—it can reduce dust entering through gaps—but make sure the exhaust fans have a clear path and that the case supports the chosen fan positions. You can connect the replacement radiator fans and reused exhaust fans to the motherboard or a suitable hub, provided the headers or hub support the combined fan power.

The main thing to be careful with is the mounting hardware, especially the screw length. Case-fan screws, radiator screws, and screws for fans mounted through a case panel can all be different lengths. A screw that is too long can penetrate the radiator and damage its internal tubes, potentially causing a leak. If the replacement fans have a different thickness from the stock fans, the included screws may no longer be appropriate, so compare the fan dimensions and use the correct hardware without forcing anything.

Yes, AIO fans can generally be replaced with other standard case fans, including reverse-blade models. You can also reuse the original fans as exhaust fans. Just match the replacement fans to the radiator’s standard 120 mm size and check whether they’re the same thickness as the originals, usually 25 mm. A push-pull setup on the radiator is another option if the case has enough room, but it may not provide much benefit for a typical build.