How is the fengshui for this layout? What will happen if the living room is directly facing the fire station?

These are some considerations:

1. Fortunately, it is not like facing a Chinese temple frontage or even any other part of a Chinese temple. Often this is considered a "greater" taboo.

2. Otherwise, frankly, it is really up to individual interpretations:

2.1. Some feel unlucky to face the fire station. As some mentioned in similar circumstances to them it is unlucky e.g. for a unit to face a hospital ground. While I suspect less so of a fire station.

2.2. A blessing in disguise is that perhaps "good" to stay near to a fire station - because hopefully of a quicker response to (touch-wood) fire incident at or near one's home.

2.3. Another blessing in disguise, is also often the fire station's height is low. So often even if one's unit's level is low, looking towards the fire station means that one may have unobstructed view.

3. As mentioned under Para 2.1. perhaps when it is time to do a re-sale, if you have such a concern, I am sure, some potential buyers may also do so. Thus... here more of a concern of trying to sell the unit. And/or unfortunately may get low-ball offers in the end. And therefore affect $$$K returns - if any.

WHITE NOSE? = SIRENS
Affect our "beauty sleep?"

P.S. In the past, whenever an activation of a fire truck, the gate(s) of the fire station will open with lots of siren lights and SOUNDS (Noise).

Hopefully, these fire-trucks don't start to ring their sirens and lights at the start of the fire station.. else this can create "white-noise" pollution. And of course, won't it be bad to hear sirens going off so often in the evenings or wee hours of the morning!