Why haven't we seen anyone's parents other than Riko and Mitobe's? Are they all neglectful or what? Fridge Horror horror hits hard when you remember what kind of person Akashi and Hanamiya and any other Jerk Jock has become.
Akashi's father has been mentioned at some point in the manga. A lot of the characters' brothers and / or sisters have been mentioned at least once, so there is some semblance of family. Also, this is Kuroko no Basket, not Kuroko no Parent. I don't see why they have to plot every character's parents and their upbringing when one Basketball match against a Generation of Miracles member takes at least 2-6 episodes.
Other than the obviously evil Kirisaki Daichi team play, are the impossibly cool moves (Thor's Hammer, Ankle Break, etc.) in Kn B actually legal to be used in real match (assuming they actually work in real life)?
I'm no Basketball expert (in fact, I was never even remotely interested in Basketball until I watched Kuroko no Basket), but some of the moves they use are indeed illegal (or at least, technically) in a real life game. For example, Himuro's Mirage Shot is illegal because if you catch the ball again right after throwing / pretending to throw it, you are basically passing to yourself. Kuroko's Ignite Pass could be considered illegal, because he originally does it with his fist, not his palm. The way Aomine shot over the top of the backboard is also illegal, for the ball can only travel behind, and not over it.
I'm sorry, I didn't read your question properly. The answer to your question is most of the realistic moves are legal, except for those I've specified above (and possibly some more).
Mirage Shot isn't illegal because Himuro catches the ball before his feet lands.
Why was Akashi even considered a part of the Generation of Miracles before obtaining Emperor's Eye? All of the members had some sort of special skill (Aomine's Formless Shots, Kise's Copycat, Kuroko's Misdirection, Midorima's Full-Court Range, Murasakibara's Defense / Offense), but Akashi didn't have anything all too exceptional before winning a 1-on-1 against Murasakibara. Not to mention that Murasakibara was obviously curb-stomping Akashi, and would have won if Akashi hadn't "awakened" his ability.
Well, they aren’t part of the Generation of Miracles just because they have special skills, but because they're exceptionally good at basketball in general as well (although they are, of course, primarily known for having distinct abilities and playing styles). Akashi was probably a noteworthy player even before fully developing his Emperor Eye (and he was obviously a great leader and had good intuitions). Besides, during that specific 1-on-1, Murasakibara had already “bloomed” and was comparatively better than the “special skill”-less, raw Akashi. That doesn’t mean Akashi wasn’t able to beat him before, but after Murasakibara’s “awakening” is a different matter.
How can Kuroko use Vanashing Drive on Kagami since the "spell" requires the latter being at sight on the player it's used on ? And don't tell me he saw himself in Kuroko's eyes.
This seems to be a plothole. The first time we see him use it is on Momoi when Kagami isn't around at all.