I missed taking the wrench from the Pigeon Brothers Sisters when I had the chance, so by the time I needed it, I didn’t know how to get it.
A few days and several puzzle chains later, I had completely forgotten in which room the Pigeon Bros. Sisters were, and I wasn’t even sure if they were still at the hotel (although I kept seeing their van parked outside).
Moreover, I wasn’t absolutely sure I had to find them for the wrench, or look somewhere else – or solve another puzzle before.
I spent several days like this (an hour or two each), stuck on that silly puzzle and not able to proceed with the game at all, since everything converged on it.
I found a wonderful non-spoilery progressive hint site (in fact, the one that served as the base for the new built-in hint system) and I looked up this specific puzzle and got three hints only:
You need a wrench – Which I already knew;
Who do you know has a wrench? – Which I also knew.
You got the Pigeons to the hotel, just take their wrench – The last part of which is what I had missed.
This was enough to solidify in my mind that indeed I had to find the Pigeon Bros. Sisters to get the wrench I already knew I needed.
After that, I had to brute-force my way through the rooms until I found them repairing the bathroom, et voilà.
Note that I had solved the puzzle already, it was a matter of focus: several days and many puzzle chains had passed in between, so I was completely removed from the context, and wasn’t sure if I had to solve the murder or the will beforehand – both of which I was trying hard to solve, and both of which were not available until I solved the wrench one.
The hints were a lot less spoilery than what I make them out to be above. They were progressive and subtle and helped me focus. Without that, I probably would have continued trying to solve the murder or the will, which was not possible at that stage.