Well, camera settings are always going to vary depending on what light you're working with. I'll do the best I can to point you in the right direction. You can start by reading the manual and understanding what the P,A,S and M modes do. Then put your camera on A or S and go out shooting, writing down what you have your settings at in a little notebook. Focal length, aperture, shutter speed, and ISO should be the main areas of focus. Or you can do like I did and just go around and shoot in Manual mode using the in-camera metering and all settings to properly expose your shots, then writing down your results. Also, an external flash can help as well but that is another "can of worms" in terms of re-learning a lot of stuff. Let me do my best to put down some guidelines...
Babies - Well, I have zero experience in this personally. If I were to guess I would say to go with the 85 1.4 or the 70-300. The 85 1.4 is fast enough that you can run a high shutter speed and crisply capture those squiggly little poop machines. The focal length on both of those is long enough that you won't have to be in the baby's face and can step back a little bit. You may need a ladder or stepstool for overhead shots. Variable ISO depending on the look you're going for. Usually midrange ISO for faster shutter.
Daytime Landscapes - I'd go with the 50 1.8 as you want a wide lens for landscapes. As for settings this is pretty much trial and error. If shooting handheld you should stay with a high shutter/low aperture but if you have a tripod then you can experiment. Usually low ISO.
Nighttime Landscapes - Same with daytime but you'll need a tripod and a long shutter exposure to let all the light in. High ISO
Sunset/Sunrise - I'd go with the same as landscapes. High shutter speed usually because of the abundance of light. Low ISO.
Daytime Sports/Action - 70-300, low aperture, high shutter to stop the motion (maybe a little slower if you want to blur the kicking players leg a little or something along those lines). ISO usually in the midrange get a faster shutter speed.
I hope this can give you a little bit of an idea but the "rules" in photography are more or less just guidelines. You need to get out there and shoot as much as possible. Hope this helps!