The light lens is really not worth the trouble in my opinion. You can see the red light projected on the underside of your counter with out it. What it does is creates a line of red between the DW door and the underside of the counter. Think a 1 unit high LED array that is used for the third brake light on some cars. If the underside of your stone is not honed or polished, the lens wont stick anyway. All this said - that model doesn't even have the projecting status light. Instead , it has a buzzer. Be sure your cabinetry opening is plumb, level , and square. Be sure the installer installs the fibre insulation between your cabinetry toekick and the unit's underside.

If you can send the drain down through the floor to a lower level P trap, you can do that. My saying this is not a recommendation "per se" in and of itself, it is just information, which may need further caveats. If the P trap for this DW is in the kitchen, you need to install a high loop. If you know what a high loop is, install that. High loop means to raise a portion of the dishwasher's flexible drain line as high as you can under the sink (e.g. with a piece of bailing wire). This will prevent contaminated water from backing into your dishwasher, unless the backup goes right up to the rim of your sink, in which case, an above-sink air-gap is the only thing that will prevent cross-contamination. The DW drain line branches into the sink drain line below the sink -- regardless of what type your faucet is. I suspect you have a contractor who I would consider a case of borderline fraud. Your contractor must know what a high loop is. He also must know that any dishwasher drain connecting to the kitchen P trap goes first through a high loop or an air gap. In both cases (high loop and air gap), the drain plumbing connection has no relationship to the faucet you chose to install. That is supply plumbing not waste plumbing. Perhaps I have misunderstood your post or you have misunderstood what you thought he said, or some other explanation is possible, et cetera. If not, you have a special case of a contractor saying that the faucet prevented him from raising the dishwasher hose in a high loop and thereby routing its waste water up first before it goes down into the P-trap and the house drain. HTH David

Thanks everyone you for your quick feedback! Quick correction to my point number 3 above. Other IKEA sinks can fit a 36" cabinet. After talking through all of these options with another IKEA salesperson today, I decided to choose this option. Will make my contractor's job much easier.

IMO, no people install hidden control exposed when the door is closes (hence hidden control). Preferably, the door should flush with the rest of the cabinet if the depth of the opening allows. Your model should have other means to show the status of the DW, such as projecting colored light and/or remaining time on the floor, etc. You are free to open the door when the DW is working to check additional status information and/or change settings/programs. Actually the control and/or display may not even work when the door is closed as they are supposed to be hidden. The gasket you mentioned should kinda be bent or compressed against the sides of the DW opening so that noise or moisture is somewhat blocked.