1) www.mbusa.com has a feature called owners online, I use it but forget some details for use, but I know that I've downloaded my owners manual there.
Also has a feature to use as a diary for vehicle maintenance.

2) that rear red tab dipstick is for transmission fluid fill

2) actually not having an oil dipstick tube means you don't have to worry about a leak at the bottom tube junction - just trying to find something positive about it.

3) the plastic engine cover pops up by hand ( no tool to unfasten needed ) though to access the air elements need a torx or hex, I forget which. Some mechanics dab a slop of grease or plastic lubricant on the ball tabs that the air housing pops onto during refitting.

4) wheel lugnuts I am not certain for your car, but if you tighten to around 85 ft lb you can retighten once you get the correct number.