I think in your proposed location which is after the anti-siphon you would lose the prime on the pump because you would be pulling a vacuum on the a-s. If you move it to the other side of the a-s by the exchanger I don't see why it wouldn't work. You always want to keep the run to the pump as short as possible but as long as there are no air leaks in the supply line and the pump is close to the water level it should prime OK and pull water through everything. The danger I suppose is that you risk losing the engine if a small air leak does develop in any of the components in the supply line and the pump loses it's prime.
SV Laurie Anne
1988 Brewer 40 Pilothouse