Sounds nitpicky, but does anyone think or know that there is no problem to wear a short sleeve dress type (collared) shirt in the evenings for "smart casual" (for men). I wouldn't think Polo type shirts would be OK, but does anyone know that for a fact?

No problem with either style shirt.

As long as the shirt has a collar, it will be fine. HAL recently relaxed its dress code, having just smart casual and formal nights (no more informal, which fell in between). The only types of shirts specifically excluded are T-shirts and tank tops.

More on this topic is here, directly from HAL.