No worries man, picking a camera is much easier than a notebook/desktop And they are much easier to maintain too~
I thought Canon's community is much better here in LYN, or even Malaysia?  XD
You are right, Sony's NEX lineups consist of mirrrorless cameras; whereas Sony Alpha consists of their DSLR or "DSLR".

Correct again~
D3200 is the successor to the D3100, and D5200 to the D5100. But in the camera world, newer isn't always better.

Most of the time beginners compare D3200 with D5100 (assuming Nikon only lol) since they usually start with a budget of RM2k. If you need more megapixels and better recording capabilities, go for the D3200. If you need a flippable screen and slightly better ISO performance (better performance at night/dim conditions), then pick the D5100 Most go for the latter Since you have the budget, go for the one that comes with the 18-105mm kitlens (instead of 18-55mm)

Yeah, with prime lens the user will be forced to walk around and compose their shots. And that is not exactly a bad thing, since most of the time, using a prime lens will get you better composed photos yo Most users experienced an improvement in composition after using a 50mm F1.8 lens, most of the time the 2nd lens people buy after they have mastered using their kitlens and DSLR.

Higher ISO means higher "film" sensitivity = brighter photo, good when taking shots indoors or during the night. But higher ISO also means more digital noise in your photos. So have to learn which settings to use depending on location and available lighting. Noneed worry too much about these 1st, for a beginner, just go and have fun shooting under the sun and you will be alright haha XD

As what exquisite_markas has mentioned. THe aperture opening is indirectly proportional to the F value; lower F value = larger aperture, more light comes in = brighter photo. Larger apertures (low F value) will also mean better bokeh (blur) in out-of-focus parts; whereas smaller apertures (high F values) will ensure everything in your photo is sharp (like photos taken with compact camera/ handphones)

An example of bokeh (notice how only the eyes of the cat is sharp? Everything else is blurry):

Cute Kitten 1 by PF T.J., on Flickr
Yeah, a good way to try out the "feel" of a prime lens haha