I dont have any of those issues on my 4 year old Korean built car so dont go looking for trouble that may not be there... relax!
However, that rear washer problem was present on the 2008 model Hy Coupe my daughter bought recently and the dealer replaced the motor as a fix... after I pointed it out... it now works fine.
You can check if its likely to be failing by looking at the front spray nozzles when operating the rear washer. Any dribbles from the front spray nozzles & the motor will soon be failing.
Always use a top quality windscreen washer fluid at the correct mix... avoid dishwashing up liquid as its full of salt, and water all on its own can breed bacteria which will block up pipework and nozzles.