You should probably get a louder smoke decetor if you can barely hear it upstairs.
I'm going to go with the DIY approach;
For the water sensor, I'd look into the possibility of linking the basement alarm to a speaker upstairs. I've no idea what kind of alarm you're looking at or what the electronics are like. Theoreticaly, you can jump off the audio signal just before it reaches the speaker. Send the audio signal through an amp (located close* to the alarm, preferably where it won't get wet) and connect it to a speaker upstairs.
I would never try to mess with a smoke detector I rely on, but a water sensor...buy two and have fun.
*the amp is to overcome voltage drop in the new cable, I doubt that the sensor electronics will be capable of driving a seperate speaker with at least 30 ft of cable between it.
Why do you use private tabs if you keep them open? That defeats the whole purpose.
Private tabs do not grant privacy on the open web I.e your data is still sent to Google
Private tabs tab give you local privacy - only local data history is not stored, downloads not logged, etc.
Edit: and the answer is!!! private mode could be used in place of a profile for different website sign ins. Creative.