Lucidstuck II

Depending on how much the facility relies on security cameras and other electronic devices as a means of detecting intruders, I would also suggest(if possible) carrying around an EMP charge that would disable all such devices in a radius - that is, of course, only if we're going by video game logic of a compact enough device like this existing at all and being efficient. Same with the radar and the stealth suit - we don't know how that efficient that will be, and we could end up wasting a valuable item slot on it.

I second the harpoon/hookshot crossbow and the swiss army knife/spy multitool, those would be very important I feel like. Explosives can also be fun(especially with what I have in mind). What we're lacking now though is a stealthkill melee weapon - like a string to subdue guards or a knife to backstab them(unless that's included in the multitool)

As for the infiltration itself, I doubt we will be able to get far from the heavily guarded front entrance. Take the back door, getting past the guards there wouldn't be much of a problem with a distraction or two. Once we're inside, we will most likely need to short out the power, take out the generator or use the EMP - with the lights out, not only the security cameras/laser detectors are disabled, but none of the guards will be able to raise an alarm either if we encounter them. Then we quickly take the treasure if we get out, possibly using explosives.

Although we could attempt a "pacifist" run, the problem here is that we only have one shot at this. With that in mind, I feel like we'll pretty much have to kill at least one of the guards to acquire a disguise Hitman style, which will drastically increase our chances.