Yes I could google it but what is the fun in that?
So why was the main character kidnapped?
Are the non-wood, non-green people running around supposed to be human? Is there a backstory there on why there are planets full of humans off Earth?
Am I being super nerdy by over thinking GOTG?
Food run. (‘They wanted to eat you, and I stopped them!’)
No. The Marvel Universe has multiple alien species who are identical (to a purely visible check) to humans. Xandarians (most of the human-looking aliens in GotG are presumably Xandarian) are among them.
I don’t believe it happens that way in the comics; he is an astronaut. But in the movie, Yondu does it at the behest of Quill’s real father (J’Son of Spartax in the comics) but decides to not turn him over after all.
Some are unrelated Rubber-Forehead Aliens, some are experiments on human populations (especially in the main MCU see: upcoming Inhumans) or hybrid races. E.g. Gamora is Zen Whoberi, who are all dead, and Nebula is Luphomoid. Kree (Ronan’s race) has some individuals who are indistinguishable from white humans although many are blue.
ETA: and Drax is human. Sort of.
Only in the comics. It’s not specified what Drax’s race is in the movies, but they’re not human.
I don’t think they specify anything though? He doesn’t understand the subtleties of English (or Space-English), but amnesia. There’s already talk about including his daughter for the second one, and I can’t imagine not paying some lip service to the original lore in some fashion, retconned as it is. I also didn’t get the impression that Ronan really remembered anything about Drax, except just to taunt him.
Yes, he mentions his wife and daughter by name (Hovat and Kamaria), and makes a handful of offhand remarks about things from his world. (Like one of the animals they hunted.)
It’s basically impossible to know much background until it’s explained in story. Comic stories pretty much just make up an entirely new reality every time they start a new story. Everything has had so many versions that they might be using, or very likely inventing a new one as they go along. You just can’t know anything with any certainty until they get around expositioning(exposing sounds wrong in that context ;))it to you.
They had one small exchange near the end that showed that was all a lie. Something like “that kid turned out pretty useful” “yeah, glad we decided to keep him instead of bringing him to his dad like we were hired to do”. Though I assume you are part joking.
Yeah. I couldn’t remember why they brought him on, so I just went with the gag.
Most of the humanoids are unrelated, but Thanos, in the comics, is related to humans I believe. A long time ago the Celestials came to Earth and experimented with early humans, and one of the results was a race called the Eternals. A civil war broke out resulting in some of them leaving Earth to build a colony on (around?) Uranus. Later a group of those Eternals ended up stranded on Saturn’s moon Titan and formed a colony there. Thanos is one of those Titans.
Why does Deja Thoris look human? Or Ming the Merciless? Or Mr. Spock? Or the Doctor? Human-looking aliens are an ancient and venerable science fiction trope, dating back to the dawn of the genre. If Marvel wants to carry the torch, good for them.
Alessan: total agreement. At first, of course, it was a limitation of the technology. But it also was more likely to be appealing to the audience. The average movie-goer is going to identify more closely with a humanoid alien than with something truly “out there.”
To me, the joy is how far we’ve come with CGI. We have a raccoon and a tree as major characters, and we can identify with them!
Rocket and Groot are way cooler than Chewbacca.
What always got me was that Deejah Thoris looks human, and can interbreed with the supposedly-human John Carter, but she lays eggs. Is her reproductive system similar to ours, or not?
Of course, it simplifies considerably once you let go of the assumption (which is really quite poorly supported) that Carter was human in the first place.
Rule #8 of sci-fi: All humanoid aliens are sexually compatible. 
Rule #9 - so are the non-humanoid ones.
rule #0101 - so are the holograms.
Also known as the Captain Kirk Rules.
Um I never said I had a problem with it, I’m just used to the more terrestrial Marvel movies aside from Thor and wanted to know what exactly was the setting for this adventure.
I have a theory since nothing was said either way at the end of the recent film adaptation that the Martians are human offshoots, this is backed up by the changes made to the plot from the books and the white martians meddling on earth and mars and the transport points.
So if a second film had been made, no egg laying.