A majority of those things are not a problem, and many don't even need to be fixed ASAP. It almost sounds like the mechanic nit picked the car to try to nickle and dime you. Adjusting the whipers is like a 5 minute job or less, but they will charge you about 20 bucks to do it. YOu should turn your attention to breaks, belts, and alternator. Thoes are the major things that need to be fixed. Everything else can be done in time. Do the ECU codes next. All are rather easy to fix with simple hand tools. Check out the 4th gen section of maxima.org for detailed how to's on every problem you have. There are even instructions there on how to pull ECU codes and find out other things that are broken.
These cars are generally fantastic. Dont get discourage. Working on them isn't all that hard as long as you have a decent metric set of tools.