Get a little piece is SS chain. No Paracord is not food safe and will leech chemicals in the heat of water.

You need to know the material before making a stain come out or risk damaging the material itself. Photos can help ID the material.

Some materials will require spot treatment while others may want to have a uniform coverage to make the material all look the same.

You would need to make an acoustic panel in your basement at least around the wall where the vent and duct is. You could use acoustic foam around the duct to prevent sound to some degree. But it sounds like you have a vent that is having sound transferred through it.

Since you cannot block the ventilation you will need to create barriers that prevent sound from entering closer to the sound source or at least a little ways away from the vent.

There are many places around the US, particularly in areas near boaters that have the handle lock removed to prevent over fills.

I think that Hawaii doesn't have the lock on any pump handles. And certainly I know that Maui doesn't.

You may want to check out hostels that have a PT work/stay setup or IT internships that can provide housing. There are options out there depending on where you want to go but you may have to work hard with a job or two along with college. It's not impossible, but it is what many would consider difficult.

Just spend the time to research and make a solid plan and backup. If you can manage to leave your house amicably, you may want to consider how to strategically remove yourself on good terms. Wish you all the best. Keep asking questions!