From radiators to relationships, ask anything you'd like to ask "dad."
Regular water can cause buildup of deposits and minerals which will eventually clog the jets that spray onto your windshield. If you're not going to use proper wiper fluid at least use distilled water.
Personally for three bucks I prefer the real stuff that causes water to bead off the glass and prevents bug splatter. Totally worth it.
No need to match, but I like you use up what I've got before refilling just 'cuz. If you live in a place with particularly brutal winters (I've seen this in Wisconsin and Minnesota plenty, but less so in Colorado where I live now) there's a purple kind that's good for melting very light frost, and it'll better withstand the really crazy low temperatures. But in summer, I like the normal blue stuff to actually clean the windshield.
I believe so, but better yet (if your car will not be subjected to freezing temperatures) is to just use water. WW fluid contains VOC's which contribute significantly to pollution.
California Environmental Protection Agency Facts About Windshield Washer Fluid for Your Automobile
https://ww2.arb.ca.gov/sites/default/files/2020-04/Remediated_windshield_washer_fluid.pdf
Noooo don’t use water unless you’re in a climate that NEVER freezes. I drove my grandpa’s car to Utah from Seattle and used the wiper fluid as I was coming down snoqualmie pass and froze the whole windshield because he had put water in and I almost died. DO NOT use water unless you’re 100% sure your car will never be in freezing temperatures.
And to answer the main question, you should be good to use any wiper fluid.