Where you’ve used ‘LaserBeamPSC->Activate()’ - Try using ‘SetActive(true, true)’ instead, I’ve usually had more luck with that one!
Also, it’s possible that unless the beams locations are close to the actual emitter itself, they might be being culled by it’s bounds. To get around that (temporarily) you could just massively increase the bounds in the particle system itself and ensure that ‘Use Fixed Bounds’ is checked