Persistence beats resistance 100% of the time. 

Of course listen to the kids but do not let them drive your decision.Kids can be more conservative and resistant to change than the worst adult.

While I disagree that short term rentals aren't good for a community (think room tax revenues and tourist spend), I do think there are places where it's easier and sometimes it's about the path of least resistance! 

I know there are waterproof/water resistant, etc.

Path of least resistance is to push the tenant to move out by the notice date.

Be prepared for any resistance.

I can't resist, I ask: "May I ask what that noise is during the night, it's not at all an issue, I am just curious".

Besides being not very energy efficient, plexiglass is very impact resistant meaning, in a fire you/the fire department would need to literally knock the window out of the frame to get out/in VS breaking the glass out with a tool/chair.  

I agree that it's a shame to remove slate though because it's such a beautiful roof surface that is extremely resistant to the rough New England weather: wind, hail, freeze/thaw cycles and even fire resistant which is why it is valuable (that and a new slate roof is ridiculously expensive).

@Zachary Bellinghausen I would resist decreasing the rent if it all possible.